Dissertations / Theses on the topic 'Organocatalyse énantiosélective'
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Roux, Christèle. "Aux frontières du transfert d'acyle par organocatalyse nucléophile énantiosélective." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4378.
Full textAlongside metallocatalysis and biocatalysis, organocatalysis has emerged as a complementary and powerful tool that can circumvent limitations associated to the use of metals or enzymes. Because of the growing interest for new innovative methodologies useful for complex molecules synthesis, we get interested in the preparation of versatile building blocks present in many bioactive molecules: tetrahydropyrans (THP) and polypropionates. Based on the diastereoselective formation of primary meso diols, our strategy involves an original organocatalyzed desymmetrization of these compounds by asymmetric acyl transfer. This approach allows the enantioselective synthesis of pentasubstituted THP which were valorized through the synthesis of polypropionates bearing four consecutive stereogenic centers. In addition, this new methodology provides cyclic and acyclic scaffolds with several all carbon quaternary stereogenic centers. It represents the first example in organocatalyzed asymmetric desymmetrization by acyl transfer using a chiral dialkylaminopyridine. Although asymmetric organocatalyzed acyl transfer has been widely studied since the late 90s, several investigations are currently underway to access to new chiral nucleophilic catalysts. Following the recent work of Steglich and Vedejs, we were interested in the development of new chiral organocatalysts derived from 1,6-naphthyridine. Their applications in nucleophilic catalysis have then been evaluated in kinetic resolutions of alcohols and in asymmetric Steglich rearrangements
Roux, Christèle. "Aux frontières du transfert d'acyle par organocatalyse nucléophile énantiosélective." Electronic Thesis or Diss., Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4378.
Full textAlongside metallocatalysis and biocatalysis, organocatalysis has emerged as a complementary and powerful tool that can circumvent limitations associated to the use of metals or enzymes. Because of the growing interest for new innovative methodologies useful for complex molecules synthesis, we get interested in the preparation of versatile building blocks present in many bioactive molecules: tetrahydropyrans (THP) and polypropionates. Based on the diastereoselective formation of primary meso diols, our strategy involves an original organocatalyzed desymmetrization of these compounds by asymmetric acyl transfer. This approach allows the enantioselective synthesis of pentasubstituted THP which were valorized through the synthesis of polypropionates bearing four consecutive stereogenic centers. In addition, this new methodology provides cyclic and acyclic scaffolds with several all carbon quaternary stereogenic centers. It represents the first example in organocatalyzed asymmetric desymmetrization by acyl transfer using a chiral dialkylaminopyridine. Although asymmetric organocatalyzed acyl transfer has been widely studied since the late 90s, several investigations are currently underway to access to new chiral nucleophilic catalysts. Following the recent work of Steglich and Vedejs, we were interested in the development of new chiral organocatalysts derived from 1,6-naphthyridine. Their applications in nucleophilic catalysis have then been evaluated in kinetic resolutions of alcohols and in asymmetric Steglich rearrangements
Dudognon, Yohan. "Synthèse et utilisation de composés 1,3 - dicarbonylés en organocatalyse énantiosélective." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4357/document.
Full textThis thesis focuses on the development of new reactions using 1,3-ketoamides in enantioselective organocatalysis to access structures never obtained before and on the development of a new synthesis of original 1,3-dicarbonyl compounds and their use in organocatalyzed reactions.Firstly, we describe all our attemps of -functionalization of acyclic unsubstituted 1,3-ketoamides by enantio- and diastereoselective Mannich reaction, by enantioselective amination reaction and by enantioselective Lossen rearrangement. Then, we address how 1,3-ketoamides allow us to achieve the regio- enantio- and diastereoselective multicomponent synthesis of 1,2,3,4-tetrahydropyridines, a scaffold never reached previously as well as the synthesis of another family of complex heterocycles, 2,6-DABCO.Secondly, we detail the development of a new synthetic methodology, based on the addition of silylated nuclophiles to -oxoketene intermediates, generated by Wolff rearrangement triggered by microwave irradiation. This way, masked 1,3-ketoaldehydes, primary 1,3-ketoamides, fused bicylic furan-3-ones and a masked 1,3-ketoacyl azide have been synthesized. The use of these original substrates in enantioselective organocatalysis will be discussed as well
Dudognon, Yohan. "Synthèse et utilisation de composés 1,3 - dicarbonylés en organocatalyse énantiosélective." Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4357.
Full textThis thesis focuses on the development of new reactions using 1,3-ketoamides in enantioselective organocatalysis to access structures never obtained before and on the development of a new synthesis of original 1,3-dicarbonyl compounds and their use in organocatalyzed reactions.Firstly, we describe all our attemps of -functionalization of acyclic unsubstituted 1,3-ketoamides by enantio- and diastereoselective Mannich reaction, by enantioselective amination reaction and by enantioselective Lossen rearrangement. Then, we address how 1,3-ketoamides allow us to achieve the regio- enantio- and diastereoselective multicomponent synthesis of 1,2,3,4-tetrahydropyridines, a scaffold never reached previously as well as the synthesis of another family of complex heterocycles, 2,6-DABCO.Secondly, we detail the development of a new synthetic methodology, based on the addition of silylated nuclophiles to -oxoketene intermediates, generated by Wolff rearrangement triggered by microwave irradiation. This way, masked 1,3-ketoaldehydes, primary 1,3-ketoamides, fused bicylic furan-3-ones and a masked 1,3-ketoacyl azide have been synthesized. The use of these original substrates in enantioselective organocatalysis will be discussed as well
Gicquel, Maxime. "Organocatalyse par les phosphines : synthèse de spirooxindoles et utilisation de phosphahélicènes en catalyse énantiosélective." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS071.
Full textThis last decades, phosphine organocatalysis became an important field in organic chemistry. Various groups showed the potential of phosphines to promote a lot of reactions. For example, Rauhut-Currier reaction, Morita-Baylis-Hillman reaction, Michael addition or cyclizations can be promoted by phosphines. During this thesis, we were particularly interested by cyclization reactions. Moreover, spirooxindole scaffold being present in many bioactive and natural compounds, we focused our attention on this scaffold. A [3+2] cyclisation methodology between electron poor olefins and allenoates has been developed to have access to a new family of highly functionalized spirooxindoles. These compounds being analogs of well know MDM2-p53 interaction inhibitors, we then evaluated them as anticancer agents. One of these compounds showed an inhibition constant (IC50) of 13 nm, which is similar to inhibitors previously describe. During the scope of the [3+2] cyclization methodology, a new reactivity of allenoate has been discovered. Indeed, allenoates bearing benzyl group on gamma position are able to induce [4+2] cylizations. With this new reactivity in hand, a family of highly susbtituted spirocyclohexane-oxindoles have been synthesized. This manuscript also reports the use of new family of chiral phosphines bearing a helical chirality and named phosphahelicenes. These helical catalysts were able to promote [3+2] cyclizations between electron poor olefins and activated allenes with enantiomeric excesses up to 97%. These cyclizations are the first examples of the use of helical phosphines in organocatalysis with high level of enantioselectivity
Dobrota, Cristian. "Phospholanes chiraux : synthèse et utilisations en catalyse énantiosélective." Paris 11, 2005. http://www.theses.fr/2005PA112193.
Full textThis thesis deals with the synthesis of new chiral P-aryl and P-alkyl-2-c,5-t-diphenylphospholane as ligand in homogenous asymmetric catalysis. In the first part are presented two aspects of preparation of P-aryl-2-c,5-t-phospholane from catalyzed palladium coupling reaction. Synthesis of 8 new compounds is described from secondary phosphine oxyde or phosphine-borane complex. The second chapter devoted the synthesis of P-alkyl-2c, 5t-diphenylphospholane using an efficient and original strategy of alkylation of secondary phosphine by alkyltriflates. The third chapter presents the results in homogenous asymmetric hydrogenation of olefins. In the first part, the efficient activity of 1,2-bis-(2,5-diphenylphospholanyle)ethane ligand is illustrated in hydrogenation reaction of prochiral olefins. The second part describes the use of the new phospholane compounds as ligand in rhodium catalyzed hydrogenation. The similar results obtain from free phosphines and the corresponding tertiary phosphonium salts confirm the advantage to use the salt as ligand precursor. The fourth chapter summarize the result in the Morita-Baylis-Hillman reaction catalyzed by P-méthyle-2,5-diphénylphospholanium. If the results are modest, there is a great potential to use P-alkyle-phospholane in organocatalysis
Poisson, Thomas. "Nouveaux développements en organocatalyse : du dédoublement d'alcools à la protonation énantioselective organocatalysée." Rouen, 2008. http://www.theses.fr/2008ROUES051.
Full textThis work deals with the development of new organocatalysis tools for organic synthesis. First, we have performed the functionalization of the 4-(dimethylamino)pyridine scaffold. This functionalization has furnished three original organocatalysts which were evaluated in two reactions : the secondary alcohol resolution and the Steglich rearrangement. During the course of this study we have discovered a new transprotection procedure of O-silyl compounds into O-benzoyl compounds. In addition, we have performed the first organocatalytic enantioselective protonation of silyl enolates mediated by cinchona alkaloids and a latent source of HF. This process was simplified by the use of carboxylic acid and cinchona alkaloids. This two approaches leads to enantioselective proton transfer with enantioselectivities up to 92% ee. Finally this methodologies was applied to the enantioselective synthesis of homoisoflavones and isoflavones with enantioselectivities up to 81%
Saidah, Milane. "Synthèse énantiosélective de gamma-lactames possédant un centre tétrasubstitué." Electronic Thesis or Diss., Aix-Marseille, 2023. http://www.theses.fr/2023AIXM0034.
Full textIn view of the emergence of organocatalysts compounds as powerful tools for asymmetric catalysis, the development of processes involving chiral ion pairs has proven successful. Notably, Asymmetric Counterion-Directed Catalysis (ACDC) is well-known to be an efficient strategy for enantioselective reactions involving cationic species and enantiomerically pure counteranions. More specifically, cyclic N-acyliminium ions are key intermediates in the preparation of enantioenriched gamma-lactams. Based on the concept of ACDC, this work has focused on the construction of tetrasubstituted carbon centers via an organocatalyzed alpha-amidoalkylation reaction by chiral phosphoric acids from gamma-hydroxylactams
Merad, Jérémy. "Synthèse énantiosélective organocatalysée de 1,3-diols acycliques par amplification de type Horeau." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4357.
Full textAcyclic 1,3-diols are ubiquitous scaffolds, essential in the structure of numerous natural products. The developpment of innovative pathways allowing their enantioselective obtention is of first interst in organic synthesis. In this context, our team envisaged a strategy of multiple organocatalyzed enantioselective acyl transfers. This approach led to the implement of a methodology based on the organocatalyzed desymmetrization of meso 1,3-diols. The desymmetrized compounds were obtained with high level of enantioselectivity and were used as useful building blocks easily valorizable in total synthesis. In a second time, we developed an organocatalyzed method of double kinetic resolution (DoCKR) of anti 1,3-diols. Very general, practicable and useful, this process allows the preparation of enantiopur diols with a large structural diversity. The particularity of these methods reside in the exploitation of the Horeau principle leading to the amplification of the enantioselectivity. These phenomons of kinetic amplification, often anecdotic, were used in this study as a powerful tool.The employed isothioureas belong to the nitrogenated Lewis bases family which were discovered only very recently to promote enantioselective acyl transfer. Although their uses in enantioselective catalysis were rapidly democratized, the structural feature responsible of their selectivity are not all clearly identified. To establish a relationship between structure, reactivity and selectivity of theses molecules, new isothioureas were synthesized and evaluated in enantioselective catalysis
Quinonero, Ophélie. "Synthèse organocatalysée énantiosélective de 4-arylpyridines atropoisomères par conversion de chiralité centrale à axiale : application vers la synthèse totale de la streptonigrine." Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4350.
Full textThis work focused on the development of central-to-axial chirality conversion methodology for the synthesis of 4-arylpyridine atropisomers, and its application in total synthesis. In the first place, synthetic methodology was optimised for the synthesis of enantioenriched and hindered 1,4-dihydropyridines. At this point, the challenge was to find the right compromise between selectivity and reactivity to get enantioenriched dihydropyridines with sufficient bulkiness around the C4 position, for formation of stable 4-arylpyridine atropisomers after conversion of the chiral center (C4) to a chiral axis. A detailed screen was performed to find the optimal oxidation conditions leading to moderate to full chirality conversion. Based on this strategy, the total synthesis of (+)-streptonigrin, a natural product containing a 4-arylpyridine framework, was planned following two main pathways using organocatalytic transformations as key steps
Fleury-Brégeot, Nicolas. "Etudes sur la synthèse énantiosélective d'hétérocycles azotés par catalyse nucléophileDéveloppement de nouveaux catalyseurs phosphorés." Paris 11, 2008. http://www.theses.fr/2008PA112300.
Full textAsymmetric organocatalysis is a new developing field in organic chemistry. During this work, an enantioselective version of the phosphine catalyzed [3+2] cyclization reaction between allenoate and imine has been studied. Good results have obtained with the use of the binaphthophosphepines with enantiomeric excesses up to 80 %. A bulkier protecting group on the nitrogen of imine allows even better results (ee>90 %). The scope of this reaction has been extended to new substrates : allenic phosphonates. They also have been used with success in the [4+2] cyclization reaction with imines. Concerning the [3+2] cyclization reaction, preliminary results in asymmetric version are promising with ee’s up to 68 %. Then according to the low quantity of efficient chiral phosphines in organocatalysis, we decided to design a new family of phosphorus organocatalysts : 2-phospha[3] ferrocenophanes. Several phosphines have been synthezised with either central or planar chirality and then evaluated in various organocatalytic tranformations. Phosphaferrocenophanes with planar chirality gave excellent results both in terms of catalytic and enantioselectivity levels. These new chiral phosphines represent a new family of chiral auxiliaries for organocatalysis
Roudier, Mylène. "Catalyse duale pour une synthèse énantiosélective éco-compatible." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4347.
Full textThis manuscript is focus on the development of multicatalyzed reactions involving iminium activation and reversible neutral hydrogen transfer reaction for the synthesis of complexe enantioenriched building blocks from allyl alcohols and 1,3-dicarbonyls.An unprecedented cascade catalysis combining an iron catalyst and a pyrrolidine-base catalyst is developed for the preparation of g-fonctionalized enantioenriched alcohols in a formal redox-, atom- and step-economical approach. The efficiency of this method involving a dual catalysis and a retro-Claisen xas further demonstrated in the short synthesis of several key fragments of biologically active natural products or odorant molecule. This methodolgy was then incremented by a experimental mechanistic study allowing a better understanding of the mechanism of this transformation and leading to a new catalytic systeminvolving three different catalysts (iron complex, copper and organocatalyst). Then, we focused on the development of a new synthetic approach to enantioenriched medium-sized lactones. This methodology is based on a 1,4-Michael addition of cycloalkane-1,3-diones to a,b-insaturated aldehydes. Then, a key chemoselective reductively triggered Claisen fragmentation occurred to generate desired lactones in a rapid manner.Finally, thanks to our methodology developed during this thesis, the total synthesis of floribundane B was studied
Bouillac, Pierre. "Nouveaux développements en organocatalyse énantiosélective : activation duale d’éthers d’énol silylés désymétrisation atroposélective de maléïmides N-aryle." Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0176.
Full textThis thesis work makes a contribution to the enantioselective organocatalysis field within two research axes. The first consisted in the valorisation in stereoselective catalysis of silyl enol ethers compounds as 1,3-ketoaldehydes surrogates. Theoretical and experimental studies enabled a proposal for the rationalisation of the observed diastereoselectivity during the formation of these compounds by oxoketene intermediates hydrosilylation. Then, a methodology involving these silyl enol ethers in a highly regio- and enantioselective chiral iridium complex catalyzed allylation process was developed. A diastereodivergent dual catalytic version was also investigated involving an unprecendented combination of chiral iridium complex and squaramide-type organocatalyst.The second research axis resided in the potential study of chiral azolium dienolate intermediates as a synthetic platform to enantioselectively access families of atropisomeric molecules. These intermediates, in situ generated from a reaction between an enal and an N-heterocyclic carbene under oxidative conditions, were engaged in a desymetrisation process of N-aryl maleimides leading to a librairy of bis-succinimide derivatives featuring a great molecular complexity consisting of 6 highly controlled chirality elements including two C-N stereogenic axes. A mechanism explaining their formation as well as a rationalisation for the observed stereoselectivity were proposed. Finally, a phtalimide compound could be prepared from the bis-succinimide derivative under basic conditions via a E1CB mechanism
Panossian, Armen. "Organocatalyse énantiosélective à l'aide de phosphines chirales : études méthodologiques et synthèse de catalyseurs à structure ferrocénique." Paris 11, 2008. http://www.theses.fr/2008PA112304.
Full textDespite the successful application of a large number of chiral phosphorus compounds as ligands in organometallic catalysis, the use of chiral phosphines as organocatalysts remains to date very restricted. In this context, we have considered the development of new enantioselective variants of phosphine-catalyzed transformations. Our first target was the use of allenylphosphonates as original subtrates in phosphine-catalyzed [3+2] annulations. A fine optimization of the reaction conditions was required to reach high conversions into the cyclized products. Some of these compounds were obtained in enantioenriched form by using a chiral binaphthophosphepine catalyst. Enantiomeric excesses ranged from 81% to 95%. Additionally, intramolecular Rauhut-Currier reactions were studied. We observed a lack of reactivity and of selectivity of the chiral catalysts which have been tested so far. Therefore, we decided to prepare new chiral phosphines specifically tailored for enantioselective organocatalysis. Among these phosphines, planar chiral 2-phospha[3]ferrocenophanes displayed interesting properties as organocatalysts. Notably, in [3+2] annulations between allenoates and activated alkenes, they yielded the cyclized products with high enantiomeric excesses (up to 96%), good yields and regioselectivities. Moreover, these phosphines proved to be robust and stable towards oxidation in the reaction conditions, which should allow their recycling and their use as supported catalysts
Basdevant, Benoît. "Synthèse énantiosélective de cétones α-tosyloxylees en utilisant des réactifs d'iode hypervalent chiraux." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/8573.
Full textLiu, Xueyang. "Dédoublement cinétique organocatalysé par stratégie indirecte." Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0584.
Full textChiral tertiary alcohols and quaternary stereocenters are important moieties widespread in natural products and pharmaceuticals, their enantioselective construction is therefore pivotal. During this thesis, we focused our interest on these motifs using an isothiourea-catalyzed indirect kinetic resolution. The strategy was decomposed in stereoselective two-steps sequence: 1) diastereocontrolled preparation of racemic substrates, secondary-tertiary diols and secondary alcohols bearing quaternary stereocenter, then 2) a kinetic resolution of the secondary alcohol indirectly controlling the adjacent center which is either a tertiary alcohol or either quaternary center. This indirect strategy, different from the previous studies, demonstrated its efficiency, its generality and its simplicity, by the discrimination of only two functional groups.On the other hand, by applying amplification of enantioselectivity on kinetic resolution of diols, we worked on enantioselective preparation of stereotriads. With this approach, several building blocks were obtained in a high level of enantioselectivity controlling the stereochemistry of fluorinated tetrasubstituted centers, of stereotriads and of a stereopentad. Finally, a straightforward access to flavonoïds was established combining the double kinetic resolution with an intramolecular nucleophilic aromatic substitution opening interesting synthetic perspectives towards a family of bioactive molecules
Pinto, Nathalie. "Organocatalyse énantiosélective par les phosphines chirales : synthèse d'hétérocycles azotés et de cycles carbonés par cyclisation [3+2]." Paris 11, 2010. http://www.theses.fr/2010PA112253.
Full textLn the last decade, the use of trivalent phosphines as nucleophilic organocatalysts has been widely developed, allowing a number of synthetically useful, original transformations to be disclosed. However, only a few enantioselective phosphine promoted reactions have been reported so far. Ln this context, we have been interested in the development of new enantioselective [3+2] cyclisation reactions catalysed by chiral phosphines. The two phosphines which were screened during this study are the (S)-tBu-Binepine and the (S,S)-FerroPHANE. (S)-tBu-Binepine proved to be a good catalyst for the enantioselective [3+2] cyclisations between allenoates and imines bearing a diphenylphosphinoyl unit (DPP) as the nitrogen protecting group. The corresponding pyrrolines were obtained with enantiomeric excesses between 73 and 88%. (S,S)-FerroPHANE was successfully used in the cyclizations between allenes and enones, allowing the highly enantioselective synthesis of a wide variety of functionalized cyclopentenes, including spirocyclic derivatives (e. E. >80%). The same methodology was applied to the synthesis of spirooxindoles by using both Binepine and FerroPHANE as chiral catalysts. Finally, we have carried out the highly diastereo- and enantioselective desymetrisations of prochiral dibenzylidene cyclohexanones by means of organocatalytic [3+2] cyclisations. These studies have demonstrated the high efficiency of chiral phosphines for the enantioselective construction of comple molecular scaffolds, starting from simple and easily available starting material
Merad, Jérémy. "Synthèse énantiosélective organocatalysée de 1,3-diols acycliques par amplification de type Horeau." Electronic Thesis or Diss., Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4357.
Full textAcyclic 1,3-diols are ubiquitous scaffolds, essential in the structure of numerous natural products. The developpment of innovative pathways allowing their enantioselective obtention is of first interst in organic synthesis. In this context, our team envisaged a strategy of multiple organocatalyzed enantioselective acyl transfers. This approach led to the implement of a methodology based on the organocatalyzed desymmetrization of meso 1,3-diols. The desymmetrized compounds were obtained with high level of enantioselectivity and were used as useful building blocks easily valorizable in total synthesis. In a second time, we developed an organocatalyzed method of double kinetic resolution (DoCKR) of anti 1,3-diols. Very general, practicable and useful, this process allows the preparation of enantiopur diols with a large structural diversity. The particularity of these methods reside in the exploitation of the Horeau principle leading to the amplification of the enantioselectivity. These phenomons of kinetic amplification, often anecdotic, were used in this study as a powerful tool.The employed isothioureas belong to the nitrogenated Lewis bases family which were discovered only very recently to promote enantioselective acyl transfer. Although their uses in enantioselective catalysis were rapidly democratized, the structural feature responsible of their selectivity are not all clearly identified. To establish a relationship between structure, reactivity and selectivity of theses molecules, new isothioureas were synthesized and evaluated in enantioselective catalysis
Cortes-Clerget, Margery. "Synthèse de nouveaux catalyseurs bifonctionnels peptidiques incluant un motif acide phosphonique pour la création de liaisons C-C énantiosélective." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCD058/document.
Full textA novel bifunctional organocatalyst library combining both aminocatalysis and phosphonic acid activation on a peptide structure was developed. Some structural variations allowed the optimization of the catalytic site. The potential of these catalysts was evaluated on the stereoselective Michael addition of aldehydes with several aromatic nitroalkenes. In optimized conditions, very good selectivities (up to 95:5 d.r. and 93:7 e.r) were achieved. Due to their high water-solubility, the catalysts were easily recyclable and reused over several cycles without any significant loss of selectivities. Mechanistic investigations were carried out to understand the exact mode of action of the catalysts. Both enamine formation and acid activation were essential for the reaction to occur. The peptide structure allows an intramolecular and stereoselective reaction
Roudier, Mylène. "Catalyse duale pour une synthèse énantiosélective éco-compatible." Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4347.
Full textThis manuscript is focus on the development of multicatalyzed reactions involving iminium activation and reversible neutral hydrogen transfer reaction for the synthesis of complexe enantioenriched building blocks from allyl alcohols and 1,3-dicarbonyls.An unprecedented cascade catalysis combining an iron catalyst and a pyrrolidine-base catalyst is developed for the preparation of g-fonctionalized enantioenriched alcohols in a formal redox-, atom- and step-economical approach. The efficiency of this method involving a dual catalysis and a retro-Claisen xas further demonstrated in the short synthesis of several key fragments of biologically active natural products or odorant molecule. This methodolgy was then incremented by a experimental mechanistic study allowing a better understanding of the mechanism of this transformation and leading to a new catalytic systeminvolving three different catalysts (iron complex, copper and organocatalyst). Then, we focused on the development of a new synthetic approach to enantioenriched medium-sized lactones. This methodology is based on a 1,4-Michael addition of cycloalkane-1,3-diones to a,b-insaturated aldehydes. Then, a key chemoselective reductively triggered Claisen fragmentation occurred to generate desired lactones in a rapid manner.Finally, thanks to our methodology developed during this thesis, the total synthesis of floribundane B was studied
Dagousset, Guillaume. "Etude de la réaction de Povarov : synthèse énantiosélective de composés diaminés organocatalysée par des acides phosphoriques chiraux." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00802712.
Full textQuinonero, Ophélie. "Synthèse organocatalysée énantiosélective de 4-arylpyridines atropoisomères par conversion de chiralité centrale à axiale : application vers la synthèse totale de la streptonigrine." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4350.
Full textThis work focused on the development of central-to-axial chirality conversion methodology for the synthesis of 4-arylpyridine atropisomers, and its application in total synthesis. In the first place, synthetic methodology was optimised for the synthesis of enantioenriched and hindered 1,4-dihydropyridines. At this point, the challenge was to find the right compromise between selectivity and reactivity to get enantioenriched dihydropyridines with sufficient bulkiness around the C4 position, for formation of stable 4-arylpyridine atropisomers after conversion of the chiral center (C4) to a chiral axis. A detailed screen was performed to find the optimal oxidation conditions leading to moderate to full chirality conversion. Based on this strategy, the total synthesis of (+)-streptonigrin, a natural product containing a 4-arylpyridine framework, was planned following two main pathways using organocatalytic transformations as key steps
Godemert, Jérémy. "Nouvelles applications de paires d'ions coopératifs en organocatalyse : déracémisation monotype de cétones par protonantion énantiosélective et réactions d'additions 1,2 catalysées par des bases de Brønsted générées in situ." Rouen, 2015. http://www.theses.fr/2015ROUES038.
Full textThis thesis deals with the development of enantioselective organocatalysed methodologies. More particularly, we were interested in the development of cooperative chiral ion pairs which exhibit bifunctional catalytic activities. The cationic part of those ion pairs is used to provide a chiral environment and to stabilise the charge development via electrostatic interactions, whereas the anionic part acts as a Brønsted or a Lewis base. The first part of this manuscript deals with the use of these cooperative chiral ions pairs in a one-pot deracemisation sequence of chiral ketones. Despite the fact that a step-by-step approach gave promising results, the one-pot sequence lead to erratic results with poor conversions reaching 30% but with good enantiomeric ratios up to 86:14. The second part of this manuscript concerns the use of chiral quaternary ammonium aryloxides and betaines which have been used either as Brønsted base or Lewis base. The potential of these catalysts was evaluated in a 1,2 addition reaction of diazoacetate derivatives to aldehydes, an alcynation reaction of aldehydes and a Henry reaction. While the two first reactions exhibited low enantioselectivities, the Henry reaction catalysed by chiral quaternary ammoniums aryloxides proved to be efficient on a wide range of substrates with acceptable to good yields, good diastereomeric ratios up to 95:5 and enantiomeric ratios up to 92:8
Segovia, Claire. "Nouvelles approches en organocatalyse énantiosélective par paire d’ions Access to polyfluorinated tetrahydropyranyl amides via Prins‐Ritter cyclization under green conditions Enantioselective catalytic transformations of barbituric acid derivatives." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMIR16.
Full textThe main purpose of this PhD thesis was the development of new enantioselective organocatalyzed reactions involving bifunctional catalysis if possible by means of ion-pairing catalysts. Firstly, this approach was applied to the nucleophilic dearomatization of pyridinium salts based upon an original bifunctional system ion pair/enamine. The 1,4-dihydropyridines were obtained with good regioselectivity albeit in low yields and enantiomeric excesses (19% yield and 32% ℯℯ max). Thereafter, a one-pot organocatalysed deracemization reaction of ketones bearing a stereogenic center at their α position was studied. The first step relied on a silyation reaction to provide a silyl enolate which was in the second step, submitted to an enantioselective protonation reaction catalysed by an original Cinchona catalyst. This sequence was applied to 13 α-substituted ketones in modest to high yields and up to 87% ℯℯ. It is worthy to note that this reaction is the only method of purely chemical deracemization reaction that does not rely on redox equilibrium
Liégault, Benoît. "Transformations catalytiques sélectives : couplage carbone-carbone par catalyse au palladium, hydrogénation par catalyse au rhodium et au ruthénium, nouveaux ligands et aldolisation énantiosélective par organocatalyse." Rennes 1, 2006. http://www.theses.fr/2006REN1S071.
Full textBos, Maxence. "Synthèse de [gamma]-lactones polyfonctionnelles chirales par catalyse énantiosélective." Thesis, Reims, 2015. http://www.theses.fr/2015REIMS017.
Full textThe development of new synthetic pathway leading to enantiopure compounds with significant structural diversity is an ongoing challenge in many fields of chemistry. The efficiency of these processes has to be evaluated, not only in term of quantitative criteria, such as yields and/or optical purities of obtained compounds, but also by analyzing the environmental impact of the different processes involved. In this work, we sought to develop new methodologies for the synthesis of polyfunctional chiral γ-lactones. The 5-hydroxyfuran-2(5H)-one, a bio-based molecule, was used as a platform to the construction of the γ-lactone ring. In the first part of our work, a variety of chiral γ-lactone displaying a great structural diversity were obtained by a one-pot sequential reaction. First, a step of enantioselective organocatalysis allowed the activation for the transfer of boronic acids on the hydroxyfuran-2(5H)-one; then the chiral adduct formed was engaged in a Passerini reaction leading to the construction of the lactone ring. In a second part, our efforts focused then on the development of catalytic asymmetric alkylation reactions leading to the construction of γ-lactones bearing an all-carbon quaternary stereocenter. Asymmetric allylic reactions were carried out with a very good control of the selectivity of the reaction by the use of palladium and iridium complexes catalysts. Theses lactones bearing an [1,5]-diene scaffold were then engaged in a sigmatropic [3,3] reaction opening a path for a new approach to the functionalization of aromatic heterocycles. Finally, the use of organic enantioselective catalysis was envisioned for the creation of all-quaternary stereocenters
Cadart, Timothée. "Fonctionnalisation énantiosélective des isoxazolidin-5-ones α-substituées dans des conditions de catalyse par transfert de phase : accès aux acides β2,2-aminés." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMIR11.
Full textThe main purpose of this thesis was to use readily available α-substituted isoxazolidin-5-ones as original building blocks for the synthesis of enantioenriched β2,2-amino acids. Phase-transfer catalysis approach, with low loading of an appropriate quaternary ammonium salt, was found to be the most efficient tool for the enantioselective functionalization of the α-position of isoxazolidin-5-ones, allowed thereby to generate a stereogenic quaternary center. This organocatalytic strategy was applied to C-S, C-C and C-N bond formation with good to excellent enantiomeric excess. Hydrogenolysis reactions of the N-O bond or ring-opening reactions via nucleophilic addition reaction led to the corresponding enantioenriched β2,2-amino acids formation. Finally, new easily available chiral quaternary tropos-ammonium salts were designed and evaluated for both the enantioselective α-sulfanylation and conjuguated addition reactions
Lemaitre, Clément. "Application et exploration de la conversion de chiralité centrale-à-axiale : développement de réactions de désaromatisations dirigées." Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0640.
Full textThe interest of biaryl atropisomer has been proven for decades in different fields such as catalysis, molecular materials, or medicinal chemistry. Despite this interest, the enantioselective synthesis of this type of compounds remains a real challenge. In this context, organocatalysis combined with central-to-axial chirality conversion represents a powerful tool. This PhD word has focused on the development of central-to-axial chirality conversion and the application to the total synthesis of a class of DPP4 enzyme inhibitors. This allowed a deeper understanding of the oxidation mechanism of the corresponding 1,4-dihydropyridines in 4-arylpyridines. In a second part, limits of chirality conversion have been explored with development of a new oxidation of electron deficient cycloxhexadienes. Finally, in a third part, the possibility to take advantage of the biaryl atropisomers to realise axial-to-central chirality conversion by hydrogenation have been studied
Nawaz, Faisal. "Design and synthesis of functionalized carbenes as organocatalysts and reaction intermediates." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4369.
Full textN-heterocyclic carbenes (NHCs) have become extremely popular organocatalysts in last decade. In this manuscript, we present our work in the design and the synthesis of a new class of bifunctional NHC organocatalysts, and their applications in enantioselective reactions with homoenolate equivalents. Additionally, a conceptually new synthetic approach to pyrid-2-ylidene carbenes is proposed and used in an original three-component reaction. In a broad sense, this work contributes to the progress of knowledge on the use of NHCs as organocatalysts and reaction intermediates
Laurent, Grégory. "Réactions de cycloadditions énantiosélectives catalysées par des dérivés d’acides de Brønsted chiraux." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112419.
Full textThis thesis works were aimed the asymmetric synthesis of optically pure heterocycles by high added value methodology. On one hand, the asymmetric organocatalysis allows using an inexpensive chiral materials in small quantities to generate chiral products, on the other hand, the cycloaddition reactions allow atom economy and the creation of several bonds in one reaction.The first part of this thesis concerns inverse electron demand aza-Diels-Alder cycloaddition reaction. These works involve 1-Azadienes and enecarbamates to generate tetrahydropyridines with three contiguous stereocenters.The products were obtained as a single diastereomer in good yields and good enantiomeric excess. The modification of substrates at various positions was possible without influencing the efficiency of the reaction.In the second part, a cycloaddition reaction between quinones and enecarbamates was studied. The use of a backbone SPINOL phosphoric acid proved to be very effective, leading to optically active 2,3-Dihydrobenzofurans. The products are isolated in excellent yields and enantiomeric excesses, but low diastereomeric ratios. These can be improved by engaging enethiocarbamates.A cascade reaction may also be carried out by forming the quinone in situ with a hypervalent iodine reagent. The scope of our cycloaddition and its variant initiated by PIDA is substantial but still needs to be improved. Different hydroquinones will thus be evaluated. The cycloadducts will later be transformed to develop this methodology.The last part concerns a 1,3-Dipolar cycloaddition reaction between nitrones and enecarbamates. If the use of a phosphoric acid has not proved effective, using a copper phosphate is convincing. Initially, the reaction shown excellent results, unfortunately not reproducible. A rigorous optimization was necessary to obtain satisfactory results. This reaction requires an assessment of its extent. Transformations are also envisaged to enhance the methodology
Legros, Fabien. "Nouvelles applications de paires d'ions coopératifs chirales en organocatalyse : utilisations dans des réactions mettant en jeu l'acide de Meldrum et ses dérivés." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR026/document.
Full textThe work developed in this PhD thesis deals with the development of new asymmetric organocatalytic methodologies implying cooperative chiral ion pairing catalysis, by using chiral ammonium phenoxides as catalysts and Meldrum’s acid derivatives as substrates. First, we used the ability of Meldrum’s acid to generate acylketenes after cycloversion triggered by O-silylation thanks to a silylated probase in the presence of a chiral ammonium phenoxide. Such an approach was applied to the synthesis of β-lactones and β-lactames following a [2+2] cycloaddition reaction with aldehydes or imines respectively. Unfortunately, the desired products have never been observed. Then, we focused on disubstitued derivatives of Meldrum’s acids and their propensity to fragment after a nucleophilic addition of phenoxide. In a first part, we have developed a one-pot desymmetrization reaction of Meldrum’s acid derivatives to form dissymmetric malonates after an in-situ alkylation of the transient carboxylate. However, despite high isolated yields, only an unsatisfactory 21% ee could be reached. In a second part, we have developed an unprecedented sequence consisting of (1) a nucleophilic addition of phenol derivatives to Meldrum’s acid followed by (2) a fragmentation with loss of acetone, leading after (3) decaboxylation to the formation of an acyclic ketene acetal which is involved in (4) an enantioselective protonation reaction to provide a wide range of enantioenriched phenolic esters with moderate to excellent yield and up to 70% ee
Nawaz, Faisal. "Design and synthesis of functionalized carbenes as organocatalysts and reaction intermediates." Electronic Thesis or Diss., Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4369.
Full textN-heterocyclic carbenes (NHCs) have become extremely popular organocatalysts in last decade. In this manuscript, we present our work in the design and the synthesis of a new class of bifunctional NHC organocatalysts, and their applications in enantioselective reactions with homoenolate equivalents. Additionally, a conceptually new synthetic approach to pyrid-2-ylidene carbenes is proposed and used in an original three-component reaction. In a broad sense, this work contributes to the progress of knowledge on the use of NHCs as organocatalysts and reaction intermediates
Goudedranche, Sébastien. "Réactions domino organocatalysées énantiosélectives à partir de cétoamides." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4354.
Full textThis work focused on the development of novel enantioselective transformations combining Multiples Bond-Forming Transformations and organocatalysis which are modern tools of organic synthesis in order to synthetize molecules of structural and biological interests. In this context, we developed two new Michael addition initiated domino reactions. The first one, a domino Michael addition-acylation, allows the synthesis of optically active spiroglutarimides starting from β-ketoamides and α,β-unsaturated acyles cyanides as new biselectrophiles.The second one, a domino Michael addition-hemiaminalizationhemiacetalization, allows the synthesis of seven-membered aza-cycles using α-ketoamides as new bis-nucleophiles
Goudedranche, Sébastien. "Réactions domino organocatalysées énantiosélectives à partir de cétoamides." Electronic Thesis or Diss., Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4354.
Full textThis work focused on the development of novel enantioselective transformations combining Multiples Bond-Forming Transformations and organocatalysis which are modern tools of organic synthesis in order to synthetize molecules of structural and biological interests. In this context, we developed two new Michael addition initiated domino reactions. The first one, a domino Michael addition-acylation, allows the synthesis of optically active spiroglutarimides starting from β-ketoamides and α,β-unsaturated acyles cyanides as new biselectrophiles.The second one, a domino Michael addition-hemiaminalizationhemiacetalization, allows the synthesis of seven-membered aza-cycles using α-ketoamides as new bis-nucleophiles
Gelis, Coralie. "Développement de réactions énantiosélectives organocatalysées pour la synthèse de molécules cycliques énantioenrichies." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS430.
Full textThe development of new enantioselective methodologies is essential for the synthesis of bioactive compounds. In this context, we were interested in using organocatalysts for the synthesis of enantioenriched cyclic molecules. In a first part will be describe chiral phosphoric acid catalyzed (3+2), (4+2) and (4+3) formal cycloadditions using enecarbamate or dienecarbamate. These catalysts are bifunctional and can interact with both cycloaddition partners leading to the synthesis of 2,3-dihydrobenzofuranes, carboannulated benzoquinones, cyclohepta[b]indoles and tetrahydroquinolines with high stereocontrol. In a second phase, we were interested in using chiral hypervalent iodine as organocatalyst. Theses compounds present interesting reactivity while being stable and not very toxic. Their use permits us to develop a lactonisation starting from flexible substrate and led to the synthesis of various heterocycles with good results
Fidaly, Kassim. "α-Alkylation énantiosélective d’aldéhydes par photosensibilisation redox organocatalysée dans le visible." Paris 6, 2012. http://www.theses.fr/2012PA066019.
Full textThe concept of SOMO activation was introduced recently in organocatalysis by D. W. C. MacMillan, enabling a large panel of new enantioselective α-fonctionnalisations of aldehydes. This new generic activation mode implies the essential need of an oxidant in stœchiometric amount to get in situ the key species of a highly reactive enaminum radical cation from the enamine. This work has been determined to correspond with a new challenge of merging two great areas of organic chemistry, photochemistry with organocatalysis. First investigations were established using catalytic amount of Ru(bpy)32+ as the electron transfer agent. Herein, we propose a new approach of photoredox catalysis, fully into line with the concept of organocatalysis, avoiding the use of any metal. Such a perspective associates a fully organic photosensitizer like xanthene derivatives as SET agent with a chiral auxiliary, within two catalytic cycles. First, the feasibility of the electron transfer was investigated on enamines. This study was then transposed to the enantioselective α-alkylation of aldehydes and was optimized taking into account notably salt and solvent effects associated with the light source providing an efficient photosensitized SOMO activation with good yields and enantioselectivities
Reviriot, Yasmin. "Combinaisons d'organocascades énantiosélectives avec des superacides : études mécanistiques et nouvelles opportunités synthétiques pour l'accès aux hétérocycles de taille moyenne." Electronic Thesis or Diss., Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0527.
Full textMedium-sized nitrogen heterocycles are an extremely important class of compounds which are widely represented in nature and can be found in synthetic biologically active substances. This PhD work has focused on the development of new original methodologies thanks to the use of powerful tools of organic chemistry that are Multiple Bond-Forming Transformations (MBFT’s), enantioselective organocatalysis and superacidic activation. This synergistic association has opened new synthetic opportunities for the elaboration of new highly functionalized medium-sized heterocycles in the non-racemic series, otherwise difficult to access by traditional routes. Based on the previous work in our laboratory, we have re-investigated a domino sequence initiated by an enantioselective organocatalyzed Michael addition giving access to original oxaza-bridged derivatives. This allowed the extension of the scope of the reaction. The surprising reactivity of these oxa-bridged azepanes in superacid media allowed the development of intramolecular cyclisation reactions, offering a one step route to complex and highly functionnalized nitrogen containing molecular polycyclic motif. Meanwhile in situ low temperature NMR experiments revealed cationic superelectrophilic intermediates and brought crucial mechanistic informations
Raimondi, Wilfried. "Nouvelles transformations organocatalysées énantiosélectives à partir de composés dicarbonyles et de nitroalcènes." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4350/document.
Full textThis work focused on the development of novel transformations combining MBFT's and organocatalysis, the latest powerful tools of organic synthesis, and involving the reactivity of nitroalkenes. We first developed a highly stereoselective consecutive Michael – [3+2] Heterocyclisation – Fragmentation reaction where two C–C bonds, one C–O bond and a cycle are formed to make optically active cyclopentanoximes bearing up to three stereocenters. These products can be converted into hydroxylamines or indoles. We then exploited the nucleophilic potential of 1,2-dicarbonyl compounds in the design of the first organocatalyzed diastereo- and enantioselective Michael additions of 1,2-ketoamides and 1,2-ketoesters onto nitroalkenes. The corresponding adducts are valuable synthetic platforms towards the synthesis of five- and six-membered carbo- and heterocycles with wide functional variety. This work led to the development of a domino transformation involving 1,2-dicarbonyl compounds and halogenated nitroolefines to efficiently access 2-carbonyl- and 2-phosphorylfuranes whose reported synthetic pathways remain rare. The first encouraging trials carried out to make atropisomers enable a potential asymmetric version of this methodology
Claraz, Aurélie. "Nouvelles applications de paires d’ions coopératifs chirales en organocatalyse : réactions énantiosélectives de protonation, de déprotonation et d’aldolisation directes vinylogues." Thesis, Rouen, INSA, 2012. http://www.theses.fr/2012ISAM0015.
Full textThis work deals with the development of new asymetric organocatalyzed methodologies. More particularly we were focused on using "cooperative chiral ion pairs" having an ammonium moiety derived from cinchona alkaloids and an anionic moiety with nucleophilic properties able to activate a reagent.Firstly, we used an in situ generated chiral ammonium amide (from the combination of an aminosilane and a quininium aryloxide) as a Brønsted base in two distinct reactions. Initially, this strategy was applied to an organocatalyzed desymmetrization of prochiral ketones by enantioselective deprotonation. Despite modest enantiometric excesses, this report constitutes the first example of an enantioselective orgonacatalyc approach. Then, an anti-selective direct vinylogous asymmetric aldol reaction of (5H)-furan-2-ones was achieved in good yields and enantioselectivities up to 94%.Secondly, we described two new catalytic cycles for the enantioselective protonation of latent enolates. By means of cinchona alkaloids and hydrogenocarbonates, enantioenriched α-substituted ketones were obtained with good enantiometric excesses up to 93% starting from the corresponding enol trifluoacetates. Finally, the nucleophilic properties of our ammonium phenoxide catalysts prompted us to develop an enantioselective protonation reaction of silyl enol ethers in the presence of phenol as achiral proton source
Raimondi, Wilfried. "Nouvelles transformations organocatalysées énantiosélectives à partir de composés dicarbonyles et de nitroalcènes." Electronic Thesis or Diss., Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4350.
Full textThis work focused on the development of novel transformations combining MBFT's and organocatalysis, the latest powerful tools of organic synthesis, and involving the reactivity of nitroalkenes. We first developed a highly stereoselective consecutive Michael – [3+2] Heterocyclisation – Fragmentation reaction where two C–C bonds, one C–O bond and a cycle are formed to make optically active cyclopentanoximes bearing up to three stereocenters. These products can be converted into hydroxylamines or indoles. We then exploited the nucleophilic potential of 1,2-dicarbonyl compounds in the design of the first organocatalyzed diastereo- and enantioselective Michael additions of 1,2-ketoamides and 1,2-ketoesters onto nitroalkenes. The corresponding adducts are valuable synthetic platforms towards the synthesis of five- and six-membered carbo- and heterocycles with wide functional variety. This work led to the development of a domino transformation involving 1,2-dicarbonyl compounds and halogenated nitroolefines to efficiently access 2-carbonyl- and 2-phosphorylfuranes whose reported synthetic pathways remain rare. The first encouraging trials carried out to make atropisomers enable a potential asymmetric version of this methodology
Sanchez, Duque Maria del Mar. "Nouvelles applications de l'addition de Michael organo catalysée dans des réactions domino multicomposés énantiosélectives." Thesis, Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30047.
Full textIn this work, we explored the potential of a Michael addition-initiated multicomponent reaction leading to 2,6-DABCO derivatives. In this context, we first studied the scope of the reaction by changing the partners and the parameters of the reaction. In view of making the process more eco-friendly, the use of ionic liquids was also investigated and found that in some cases, the ionic liquids could replace the toxic organic solvent and the heterogeneous catalyst of the reaction. Finally, the implementation of an enantioselective multicomponent synthesis of 2,6-DABCO led us to develop a new methodology of an organocatalytic enantioselective Michael addition of beta-ketoamides to alpha, beta-unsaturated carbonyls. In this way, adducts containing an all-carbon quaternary stereocenter were obtained in good yields and high to excellent enantiomeric excesses (up to 99%). The study of the reactivity of these adducts allowed the access to different families of optically active poly(hetero)cyclic compounds of high synthetic interest
Pantaine, Loïc. "Aminocatalyse et Réactions en Cascade pour la Synthèse de Polycycles Tridimensionnels." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV084/document.
Full textThe work presented in this manuscript aims to study organocatalytic reaction sequences enabling the stereoselective formation of carbon-carbon and carbon-heteroatom bonds. Various strategies have been developped for the preparation of chiral cyclic architectures, which represents an important challenge due to their presence in a vast number of biologically active compounds. This manuscript starts off by introducing the principal of organocatalysis, and more specifically the different activation means used in aminocatalysis.The first chapter focuses on the regio- and diastereoselective synthesis of cyclic hydrazine-containing bicycles in a solvent-free way. The second chapter merges de-aromatization or desymetrization with an aminocatalytic reaction sequence, to yield tridimensional enantioenriched polycycles from unsaturated aldehydes. Lastly, the third chapter concentrates on the synthesis of unsymmetrical sulfamides and their uses as substrates in aminocatalysis
Sanchez, Duque Maria del Mar. "Nouvelles applications de l'addition de Michael organo catalysée dans des réactions domino multicomposés énantiosélectives." Electronic Thesis or Diss., Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30047.
Full textIn this work, we explored the potential of a Michael addition-initiated multicomponent reaction leading to 2,6-DABCO derivatives. In this context, we first studied the scope of the reaction by changing the partners and the parameters of the reaction. In view of making the process more eco-friendly, the use of ionic liquids was also investigated and found that in some cases, the ionic liquids could replace the toxic organic solvent and the heterogeneous catalyst of the reaction. Finally, the implementation of an enantioselective multicomponent synthesis of 2,6-DABCO led us to develop a new methodology of an organocatalytic enantioselective Michael addition of beta-ketoamides to alpha, beta-unsaturated carbonyls. In this way, adducts containing an all-carbon quaternary stereocenter were obtained in good yields and high to excellent enantiomeric excesses (up to 99%). The study of the reactivity of these adducts allowed the access to different families of optically active poly(hetero)cyclic compounds of high synthetic interest
Nechab, Malek. "Synthèse et mise en oeuvre de nouveaux catalyseurs d'oxydation énantiosélectifs non métalliques." Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00107090.
Full textPour mettre en œuvre l'oxydation énantiosélective de substrats organiques, une synthèse modulable d'organocatalyseurs à symétrie C2, analogues du NHPI, a été réalisée. Certains de ces organocatalyseurs portant des fonctions carbamates ont montré de bonnes activités catalytiques lors de l'oxydation de nombreux substrats et surtout une très bonne sélectivité dans le dédoublement cinétique d'oxazolidines où des facteurs de stéréosélectivté de l'ordre de 40 ont pu être obtenus. Ces résultats, très intéressants, ouvrent la voie au développement d'une nouvelle méthodologie d'oxydation énantiosélective de substrats organiques.
Liu, Peng. "Helicoselective Synthesis of Dioxa[6]helicenes and Design of Orginal P-Stereogenic Brønsted Acid Organocatalystsx." Electronic Thesis or Diss., Ecole centrale de Marseille, 2020. http://www.theses.fr/2020ECDM0004.
Full textThis PhD thesis is composed of two main parts. First, the expedient helicoselective synthetic access to a new series of configurationally stable dioxa[6]helicenes from simple achiral precursors was developed. The helicity is created and controlled during an organocatalyzed domino Michael/C–O alkylation step, which delivers chiral 2-nitrodihydrofurans as single stereoisomers featuring both central chirality (two stereogenic carbon atoms) and a helical shape. Interestingly, this represents the first case of a catalytic chemical transformation in which both central and helical chiralities are controlled simultaneously, offering unprecedented chiral platform molecules for the synthesis of enantioenriched heterohelicenes by simple base-promoted elimination of HNO2 with excellent retention of the helical information in most cases. Secondly, a new design for Brønsted acid organocatalysis was developed in which the chirality is centered on the phosphorus atom. Chiral P-stereogenic thiophosphinic acids were synthesized in high enantiomeric excess. This opens new synthetic opportunities for both hydrogen-bonding and ion-pairing enantioselective organocatalysis. These new catalysts were used notably in Pictet-Spengler reactions delivering the products in moderate enantioselectivity (up to 47% ee). This first step validate the concept but further optimization is necessary to reach higher enantiomeric excess and to make these catalysts more general