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1
Shasha, Adelle. "Metal-Catalysed Hydroamination." Science. School of Chemistry, 2007. http://hdl.handle.net/2123/1710.
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Doctor of Philosophy(PhD),This thesis describes the synthesis of terminal and internal amino and amidoalkynes and their hydroamination (cyclisation) catalysed by the complex (bis(N-methylimidazol-2-yl)methane)dicarbonylrhodium(I) tetraphenylborate (1). A series of analogous palladium complexes were also prepared and investigated for catalytic hydroamination. The scope of the rhodium(I) complex (1) for the intramolecular hydroamination of more complex amino and amidoalkyne substrates was investigated. This was made possible with the synthesis of aliphatic substrates, namely, 4 pentyn 1 amide (3) and 5 hexyn 1 amide (4) and a number of aromatic substrates, namely, 1, 4 diamino-2, 5 diethynylbenzene (5), 1, 4-diamino-2, 5 bis(phenylethynyl)benzene (6), 2, 3-diamino-1, 4-diethynylbenzene (7), 2, 3-diamino-1, 4-bis(phenylethynyl)benzene (8), 1, 5-bis(acetamido)-2, 4-diethynylbenzene (9), N-(acetyl)-2-ethynylbenzylamine (10) and N-(acetyl)-2-(phenylethynyl)benzylamine (11). The rhodium(I) complex (1) catalytically cyclised the aliphatic 4 pentyn 1 amide (3) regioselectively to the 6 membered ring, 3, 4 dihydro 2 pyridone (64) as the sole product. Attempts to cyclise 5 hexyn 1 amide (4) to produce either the 6 or 7 membered ring were unsuccessful. Compounds 5, 6, 7 and 8 were doubly cyclised to 1, 5 dihydro pyrrolo[2, 3 f]indole (71), 1, 5-dihydro-2, 6-diphenyl-pyrrolo[2, 3 f]indole (73), 1, 8-dihydro-pyrrolo[2, 3 g]indole (74) and 1, 8-dihydro-2, 7-diphenyl-pyrrolo[2, 3 g]indole (75) respectively. The aromatic amides with terminal acetylenes 9 and 10 cyclised to give 1, 7 diacetyl pyrrolo[3, 2 f]indole (76) and N (acetyl) 1, 2 dihydroisoquinoline (77) respectively. However, attempts to cyclise 11 were unsuccessful. Thus the rhodium(I) complex (1) successfully catalysed via hydroamination both terminal and internal acetylenic amine and amide substrates, to give pyridones, indoles and isoquinolines. Cationic and neutral palladium complexes incorporating the bidentate heterocyclic nitrogen donor ligand bis(N-methylimidazol-2-yl)methane (bim; 2) were synthesised: [Pd(bim)Cl2] (15), [Pd(bim)2][BF4]2 (17) [Pd(bim)(Cl)(CH3)] (14), [Pd(bim)(CH3)(NCCH3)][BF4] (16). All of the complexes were active as catalysts for the intramolecular hydroamination reaction, using the cyclisation of 4 pentyn 1 amine (21) to 2 methyl 1 pyrroline (22) as the model test reaction. Percentage conversions, turnover numbers and reaction profiles for each complex were compared to the rhodium(I) complex (1). These studies have shown that the catalytic activity was not significantly dependent on the bim donor ligand or the choice of metal. Substitution of the bim (2) ligand with the COD ligand and the use of methanol as the solvent did impact significantly on the efficiency of the hydroamination reactions.
2
Shasha, Adelle. "Metal-Catalysed Hydroamination." Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1710.
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This thesis describes the synthesis of terminal and internal amino and amidoalkynes and their hydroamination (cyclisation) catalysed by the complex (bis(N-methylimidazol-2-yl)methane)dicarbonylrhodium(I) tetraphenylborate (1). A series of analogous palladium complexes were also prepared and investigated for catalytic hydroamination. The scope of the rhodium(I) complex (1) for the intramolecular hydroamination of more complex amino and amidoalkyne substrates was investigated. This was made possible with the synthesis of aliphatic substrates, namely, 4 pentyn 1 amide (3) and 5 hexyn 1 amide (4) and a number of aromatic substrates, namely, 1, 4 diamino-2, 5 diethynylbenzene (5), 1, 4-diamino-2, 5 bis(phenylethynyl)benzene (6), 2, 3-diamino-1, 4-diethynylbenzene (7), 2, 3-diamino-1, 4-bis(phenylethynyl)benzene (8), 1, 5-bis(acetamido)-2, 4-diethynylbenzene (9), N-(acetyl)-2-ethynylbenzylamine (10) and N-(acetyl)-2-(phenylethynyl)benzylamine (11). The rhodium(I) complex (1) catalytically cyclised the aliphatic 4 pentyn 1 amide (3) regioselectively to the 6 membered ring, 3, 4 dihydro 2 pyridone (64) as the sole product. Attempts to cyclise 5 hexyn 1 amide (4) to produce either the 6 or 7 membered ring were unsuccessful. Compounds 5, 6, 7 and 8 were doubly cyclised to 1, 5 dihydro pyrrolo[2, 3 f]indole (71), 1, 5-dihydro-2, 6-diphenyl-pyrrolo[2, 3 f]indole (73), 1, 8-dihydro-pyrrolo[2, 3 g]indole (74) and 1, 8-dihydro-2, 7-diphenyl-pyrrolo[2, 3 g]indole (75) respectively. The aromatic amides with terminal acetylenes 9 and 10 cyclised to give 1, 7 diacetyl pyrrolo[3, 2 f]indole (76) and N (acetyl) 1, 2 dihydroisoquinoline (77) respectively. However, attempts to cyclise 11 were unsuccessful. Thus the rhodium(I) complex (1) successfully catalysed via hydroamination both terminal and internal acetylenic amine and amide substrates, to give pyridones, indoles and isoquinolines. Cationic and neutral palladium complexes incorporating the bidentate heterocyclic nitrogen donor ligand bis(N-methylimidazol-2-yl)methane (bim; 2) were synthesised: [Pd(bim)Cl2] (15), [Pd(bim)2][BF4]2 (17) [Pd(bim)(Cl)(CH3)] (14), [Pd(bim)(CH3)(NCCH3)][BF4] (16). All of the complexes were active as catalysts for the intramolecular hydroamination reaction, using the cyclisation of 4 pentyn 1 amine (21) to 2 methyl 1 pyrroline (22) as the model test reaction. Percentage conversions, turnover numbers and reaction profiles for each complex were compared to the rhodium(I) complex (1). These studies have shown that the catalytic activity was not significantly dependent on the bim donor ligand or the choice of metal. Substitution of the bim (2) ligand with the COD ligand and the use of methanol as the solvent did impact significantly on the efficiency of the hydroamination reactions.
3
Sutherland, Ian Michael. "Metal-catalysed asymmetric hydrogenation." Thesis, University of Hull, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304289.
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Rountree, S. M. "Metal catalysed olefin metathesis." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517512.
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McNally, Steven John. "Metal catalysed intermolecular hydroacylation." Thesis, University of Bath, 2003. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426175.
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6
Paliga, James Francis. "Developing Earth-abundant metal-catalysts for hydrofunctionalisation." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31115.
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The iron-catalysed hydromagnesiation of styrene derivatives has been developed further from previous publications, expanding the electrophile scope to enable the regioselective formation of new carbon-carbon and carbon-heteroatom bonds (Scheme A1). A commercially available pre-catalyst and ligand were used to give an operationally simple procedure that did not require prior synthesis of a catalyst. This work also investigated the hydromagnesiation of dienes, using a screen of ligands commonly used in transition metal catalysis. An investigation into the magnesium-catalysed hydroboration of olefins was also carried out. Although mostly unsuccessful, it was demonstrated that in the presence of a magnesium catalyst, a small amount of vinyl boronic ester could be formed from an alkyne (Scheme A2). Simple magnesium salts were also investigated for the reduction of carbonyls. Lastly, this work explored the titanium-catalysed hydrosilylation of olefins, using a novel activation method developed within the group (Scheme A3). The results were compared to those published previously using traditional organometallic activation methods and attempts at identifying conditions to improve chemoselectivity were carried out.
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Stubbs, Naomi E. "Metal-catalysed and metal-free dehydrogenation of amine-boranes." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686189.
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Hall, Tracey Jane. "Mechanisms of metal-catalysed enantioselective hydrogenation." Thesis, University of Hull, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265129.
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McLean, William Neil. "Metal catalysed reactions in organic chemistry." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257123.
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Cadu, Alban. "Noble Metal Catalysed Reductions and Rearrangements." Doctoral thesis, Uppsala universitet, Syntetisk organisk kemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-272383.
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The focus of this thesis has been organometallic catalysis applied to compounds containing heteroatoms which are usually poisonous to metal catalysts, by channelling their innate reactivity advantageously. The studies described in this thesis concentrate, in the first part, on iridium catalysed asymmetric hydrogenation (papers I and II) and in the second part, on gold catalysed internal rearrangements (papers III and IV). In each case, two classes of compounds are studied: pyridinium salts or sulphurous compounds. The asymmetric hydrogenation of pyridinium compounds was performed with 2% loading of N,P-ligated Ir catalyst with I2 additive (paper I) to achieve moderate to good enantiomeric excess (up to 98%). In paper II, olefinic sulphones were hydrogenated with an efficient 0.5% catalytic loading. In most cases full conversion was obtained and with good to excellent ees (up to 99%). The products of these reductions are chiral compounds, which could constitute further chemical building blocks. Palladium and gold were used sequentially in paper III, in order to perform a “Click” thiol-yne reaction followed by a semi-Pinacol rearrangement, leading to isolated yields of up to 98%. In paper IV The gold catalysed rearrangement of alkyl-pyridinium diynes was conducted, with a number of substrates providing >90% NMR yield. A highly selective hydrogenation was performed with a heterogeneous palladium catalyst to yield single diastereomer products. This methodology consists of up to three steps, with two catalysts in one pot.
11
Sarazin, Yann. "Metal-catalysed polymerisations : from the design of new catalysts to macromolecular architectures." Thesis, University of East Anglia, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405718.
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Adams, Kirsty. "Metal catalysed cross-coupling reactions of heterocycles." Thesis, University of Huddersfield, 2013. http://eprints.hud.ac.uk/id/eprint/20889/.
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This report describes two methodology studies dedicated towards development of metal catalysed crosscoupling reactions in the synthesis of novel heterocyclic compounds. Firstly, a Heck-Mizoroki arylation reaction is reported for the direct functionalisation of tetrahydropyridines, towards the synthesis of kainoid analogues. Kainoids are a group of non-proteinogenic pyrrolidine dicarboxylic acids, which have attracted considerable interest because of their potent biological activity, including insecticidal, anthelmintic and neuroexcitatory properties. The ideal synthesis of kainoids would allow the ability to introduce various side chains at the C-4 position to access diverse pharmacologically active kainoid analogues. Tandem asymmetric Heck-Mizoroki arylation reaction and [2,3]-sigmatropic rearrangement provides a quick and efficient way to access these molecules. The Heck-Mizoroki arylation of 1-methyl-1,2,5,6-tetrahydropyridine and its hydrochloride salt is reported, with the arylation in the 3- position of the tetrahydropyridine as the major product. The reaction has been applied to a variety of substituted aryliodides, with promising results, demonstrating functional group tolerance of the method, however isolation and purification of the resulting compounds has remained challengeing. Diarylation of tetrahydropyridines has also been achieved. Secondly, a new catalytic method for arylative spirocyclisation is reported, using stoichiometric Grignard reagents and iron(III) catalysts, to induce cyclisation of 2-iodo benzyl ethers of furan in a highly stereoselective manner to produce novel functionalised spirocyclic compounds. Method optimisation and application of a variety of Grignard reagents is reported with aryl cross-coupling achieved in high yields. Alkyl- cross coupling has also been achieved with ethylmagnesium bromide Grignard reagent.
13
Gardiner, Ian M. "Studies on transition metal catalysed olefin polymerisation." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235979.
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Yang, Ting. "Transition metal ion catalysed alkyne cyclisation reactions." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505491.
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15
Shipman, Michael. "Novel intramolecular transition metal catalysed cycloaddition reactions." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46551.
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Atkinson, Benjamin. "Metal catalysed acyl transfer reactions of amides." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.665412.
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The following thesis outlines work carried out during the last three years for the development and investigation of methodologies using amides as N- and O- acylating agents. Chapter 1 highlights the range of methodologies and protocols reported in the literature that use amides as precursors for the synthesis of both functionalised amides and esters. The introduction will highlight the range of catalysts and promoters used as well as the scope of the current methodologies. As well as this it will highlight the limitations of the methodologies so emphasising where the following research fits into these areas. Chapter 2 presents the development of a transamidation methodology using zirconocene dichloride as a catalyst. The scope with respect to functional group tolerance is presented as well as the investigations into the mechanism of the reaction. Chapter 3 builds on the research presented in Chapter 2 and details the development of a more catalytically active zirconocene transamidation methodology. By the addition of a catalytic additive the temperature or time required for the reaction to be carried out could be lowered. Investigations into the mechanism were also carried out highlighting the in situ formation of an active catalytic species. Chapter 4 details the development of an operationally simple methodology for the O-acylation of alcohols using amides. Using a catalytic amount scandium triflate the substrate scope of the reaction was explored with a proposed mechanism presented based on activation of the amide.
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Alcindor, Joanne Louise. "New metal catalysed strategies for chemical synthesis." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611756.
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Nilchi, A. "Selective hydrogenation catalysed by transition metal complexes." Thesis, Kingston University, 1988. http://eprints.kingston.ac.uk/20518/.
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This work is an investigation of the mechanism by which norbornadiene, methyl oleate and methyl linoleate are hydrogenated in acetone at 30[sup]oC, 1 atmosphere or 3 atmospheres pressure, using rhodium complexes of the type [Rh(diene)L[sub]n][sup]+A[sup]-(where diene = norbornadiene , L = tertiary phosphine, phosphite, A = CIO[sup]-[sub]4 or PF[sup]-[sub]6). The results were interpreted assuming three active catalyst species, (Rh(diene)L[sub]2)[sup]+, (RhH[sub]2L[sub]2)[sup]+ and RhHL[sub]2. Also investigated were the effects of adding acid (HClO[sub]4) or base (Net[sub]3) and how this altered the equilibrium (RhH[sub]2L[sub]2)[sup]+<--> H[sup]+ + RhHL[sub]2. At atmospheric pressure, the rate of hydrogenation of norbornadiene and norbornene varies with ligand in the order PPh[sub]3 < PPh[sub]2Me < PPhMe[sub]2, suggesting that oxidative addition of hydrogen is an important first stage of the catalysis. The addition of acid, slowed the rate of hydrogenation for catalysts containing more electron donating ligands (relative to triphenyl phosphine), indicating that the monohydride was a more active specie than the dihydride. With triphenylphosphine or less electron donating ligands in the catalyst, the rate remains constant or increase slightly, indicating that an "unsaturate route" emanating from a diene complex is probably important. The catalyst containing cyclohexylphosphine ligands which are strongly electrondonating but sterically crowded is ineffective in hydrogenation, suggesting that steric crowding may cause an alternative route to operate. Higher pressure (3 atm.) causes faster hydrogenation and provided other mechanistic insights. For methyl oleate at atmospheric pressure, the rate of hydrogenation varies with ligand in the order PPh[sub]3 > PPh[sub]2Me > PPhMe[sub]2, but this order is reversed at 3 atm. pressure. The rate of isomerisation of methyl oleate varies with ligand in the order PPh[sub]3 < PPh[sub]2Me < PPhMe[sub]2, at both pressures. The rate of isomerisation of methyl oIeate and methyl linoleate is lowest, when there is no or a slight excess of acid present but is highest in presence of a base (especially for the catalyst containing diphenylmethylphosphine ligand). Mechanistic interpretations were made.
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Buxton, Craig. "Development of metal catalysed cycloadditions and cyclisations." Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.730853.
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Warrington, Adam David. "Transition metal-catalysed oxidative additions to alkenes." Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/33674.
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This thesis describes the development of new methods towards the stereoselective synthesis of oxazolidinones and [3,3] sigmatropic rearrangements to allylamines from allylic carbamate starting materials. Unlike previous protocols found in the literature the oxazolidinones formed do not have a protected nitrogen atom. The stereoselective formation of chlorohydroxylated products is demonstrated with the view to utilise this reaction as part of an alternative to the tethered aminohydroxylation. A novel diastereoselective iodine mediated cyclisation of allylic carbamates and allylic ureas to oxazolidinones and imidazolidinones respectively is described. The reaction has also been telescoped from an aldehyde completing three reactions in a one pot environment. The use of palladium (II) catalysis for oxazolidinone formation is also shown in an attempt to devise an enantioselective reaction analogous to the highly acclaimed tethered aminohydroxylation. Palladium (II) catalysis is also utilised for the diastereoselective conversion of allylic carbamates to allylic amines. Chapter 1: An overview to the uses of osmium and palladium in the activation of alkenes described in the literature. Chapter 2: Highlights our research into the formation of oxazolidinone rings from and [3,3] sigmatropic rearrangements of allylic carbamates. Chapter 3: Provides experimental data for our studies.
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Gupte, S. P. "Studies in transition metal catalysed carbonylation reactions." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1989. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3313.
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Castro, Cevallos Ursula Isabel. "Phenol oxidation catalysed by polymer-supported metal complexes." Doctoral thesis, Universitat Rovira i Virgili, 2009. http://hdl.handle.net/10803/8577.
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Focussing on the treatment of industrial effluents with high content of organic compounds, the advanced oxidation processes (AOPs) develop technologies such as the catalytic wet peroxide oxidation of organic compounds (CWPO). The improvement of this process is based on the variation either of the catalyst or the oxidant source. The present research work proposes to get advantage of the catalytic activity of homogeneous catalysts, avoiding the metal contamination of the reaction media by the heterogenization of Cu(II) ions over polymeric matrices, to finally use them as catalysts in the CWPO of phenol. From the group of synthesised catalysts, it was identified two suitable catalysts: Cu(II) adsorbed onto poly(4-vinylpyridine) with 2% of cross-linking and Cu(II) loaded in poly (DVB-co-VBC) functionalised with imino diacetic acid. Both catalysts demonstrated high catalytic activity without Cu(II) release, concluding that heterogenization of catalysts for the CWPO is an ascertained decision to promote phenol degradation.Entre los tratamiento de efluentes industriales con alto contenido de material orgánico, se encuentran los procesos de oxidación avanzada (AOPs) que desarrollan tecnologías como la oxidación húmedo catalítica con peroxido de hidrógeno de compuestos orgánicos (CWPO). El mejoramiento de éste proceso está basado en la variación tanto del catalizador como de la fuente oxidante. El presente trabajo de investigación propone aprovechar la actividad catalítica de catalizadores homogéneos, evitando la contaminación por metal del efluente mediante la heterogeneización de iones de Cu(II) sobre matrices poliméricas, para luego ser usados como catalizadores en la CWPO del fenol. Del grupo de catalizadores sintetizados, se identificaron dos catalizadores: Cu(II) adsorbido sobre poly(4-vinylpyridine) con 2% de entrecruzamiento y Cu(II) soportado en poli (DVB-co-VBC) funcionalizado con ácido aminodiacetico. Ambos catalizadores demostraron alta actividad catalítica sin liberación de Cu(II), concluyendo que la heterogeneización de catalizadores homogéneos para la CWPO es una decisión acertada cuando se desea promover la degradación del fenol.
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Teoh, Euneace Ching Mei. "Synthesis of amino acids by metal-catalysed reactions." Monash University, School of Chemistry, 2004. http://arrow.monash.edu.au/hdl/1959.1/9633.
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Lisa, Charlotte Pattenden. "Investigation ofa Metal Catalysed [3+3] Annelation Reaction." Thesis, University of Sheffield, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489732.
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Mkhalid, Ibraheem Ahmed I. "Transition metal catalysed borylation of C-H bonds." Thesis, Durham University, 2006. http://etheses.dur.ac.uk/2694/.
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Chapter one provides a general review of the metal catalysed diboration of alkynes, 1,2- and 1,3-dienes, a,ß-unsaturated carbonyl compounds, and alkenes, as well as the metal catalysed borylation of alkane and arene C-H bonds. Chapter two is divided into two main sections. The first section introduces a high yield, highly selective catalytic synthesis of vinylboronate esters VBEs, including 1,1-disubstituted VBEs, from alkenes without significant hydrogenation or hydroboration, using the catalyst precursor, trans- [RҺС1(СО)(РРhз)2], and the diboron reagents В2РІП2, В2ПЄОР2 and HBpin. The second section addresses the synthesis of VBEs via microwave-assisted catalysis and these results are compared with those from the conventional, thermal reactions. Chapter three investigates regioselectivity in the synthesis of pyridinyl and bipyridinyl botónate esters via C-H activation using the catalyst precursor, [Іг(СОВ)(ц-ОМе)]2, and 4,4'-'Bu2-2,2'-bipyridine as the ligand. Several the pyridinyl and bipyridinyl boronate esters were coupled with aryl halides by Suzuki-Miyaura cross-coupling reactions in one pot. Examples include msiture-sensitve heteroaryl 2-boronate esters. Chapter four shows the utility of the transition metal catalysed borylation of C-H bonds in the synthesis of biologically active retinoic acid analogs.
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Cook, Andrew James. "Metal catalysed approaches to novel anti-cancer agents." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411359.
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Attwood, D. "Metal ion catalysed ester hydrolysis in reverse micelles." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234927.
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Van, Der Waals Dominic. "Atom economical and environmentally benign metal catalysed synthesis." Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636541.
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The use of inexpensive metal catalysts for a range of acylation reactions including the activation of anhydrides and the aminolysis of esters. Discussion on the use of a heterogeneous copper catalyst for teh reduction of a range of organic functional groups and its use in amination of nitriles.
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Ma, Ming Ju. "Metal-catalysed synthesis in the presence of boronates." Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619220.
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Siddle, James Spencer. "Metal-catalysed cross-coupling reactions of nitrogen heterocycles." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/617/.
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Described herein are copper-catalysed N-C heteroarylations of benzimidazole, 1-methylbenzimidazolone, imidazole and pyrrole. The products of these reactions then undergo palladium-catalysed C-C cross-couplings with aryl or heteroarylboronic acids under Suzuki-Miyaura conditions to provide a rapid entry to tris(hetero)aryl scaffolds comprising two or three N-heterocyclic rings. The sequential N-C and C-C couplings can be performed in a one-pot process. 1,5-Di(hetero)arylated-pyridin-2(1H)-one derivatives have been synthesised in good yields starting from (2-fluoro-5-pyridyl)boronic acid. The sequence comprises three steps: (i) palladium-catalysed Suzuki-Miyaura reaction; (ii) basic hydrolysis; (iii) copper-catalysed C-N coupling. X-ray crystal structures are reported for selected pyridin-2(1H)-one derivatives. These compounds are of interest as new scaffolds for drug discovery. A one-pot synthesis of 2-chloro-3,4-diiodopyridine from 2-chloropyridine is described via a Directed ortho Metallation (DoM)/Halogen Dance (HD) mechanism in 26-28% yields. By performing sequential iterative Suzuki-Miyaura cross-couplings using a variety of functionalised heteroaryl and arylboronic acids, a series of novel 2,3,4-triheteroarylpyridine scaffolds have been accessed in synthetically viable yields, including sterically hindered derivatives. An iterative two-fold Sonogashira/Suzuki-Miyaura reaction sequence gave access to 5-[3,4-bis(2-phenylethynyl)pyridine-2-yl]-2-fluoropyridine in 48% overall yield. Disclosed is a novel route towards benzimidazolo[1,2-f]phenanthridines starting from 4-tert-butyl-N-(2-iodophenyl)benzamide via a intermolecular palladium-catalysed N-C bond formation and dehydration to form 2-(4-tert-butylphenyl)-1-(2-bromophenyl)-1H-benzo[d]imidazole. Performing an intramolecular C-H activation reaction on this provided 6-tert-butylbenzimidazolo[1,2-f]phenanthridine. This compound could be of interest to materials science or as a new scaffold for drug discovery. Synthesis of novel soluble, shielding auxiliary ligand 4-(4-(2-ethylhexyloxy)-2,6-dimethylphenyl)pyridine-2-carboxylic acid (G1pic) has been achieved via a five step synthesis from commercially available starting materials utilising the Suzuki-Miyaura reaction on demanding substrates. A route towards a more shielded auxiliary ligand have been explored eventually providing 3-(4-pyridyl)-1,5-bis(4-(2-ethylhexyloxy)phenyl)-2,4-dimethylbenzene as an intermediate for future work. Ir(III) complexes have been synthesised with G1pic and picolinic acid.
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Lewandowska, Krystyna. "Metal catalysed alkene addition reactions in organic synthesis." Thesis, Kingston University, 1989. http://eprints.kingston.ac.uk/20526/.
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The reaction between [CO[sub]2(CO)[sub]8] and CC1[sub]4 has previously been reported to lead to the formation of dichlorocarbene.ln the presence of cyclohexene,the carbene was reported to add to the alkene giving 7,7-dichlorobicyclo[4.1.0]heptane. This reaction has been reinvestigated and it has been shown that the principal pathway involves formation of CC1 [sub]3 radicals, which react with cyclohexene to farm almost equal proportions of twa isomers of 1-chloro-2- (trichloromethyl)cyclohexene (adduct).Carbene formation has been shown tobe only a minor pathway. A mechanism has been præposed which accounts far these findings. The addition of CC1[sub]4 to cyclohexene in the presence of a range of metal complexes has been studied. Use of ather dinuclear metal carbonyls gave a higher yield of the adduct than observed with [C0[sub]2(CO[sub]8)].The reactions were also more stereoselective. [RuC1[sub]2(PPh[sub]3)3], [RuH[sub]2(PPh[sub]3)4] and [RuH[sub]3(SiPhMe[sub]2) (PPh[sub]3)3] all gave much higher yields and stereoselectivities.lt has been suggested this is a consequence of a metal complex catalysed reaction mechanism in which radical pair formation plays an important role. The three ruthenium complexes appear to generate the same active catalytic species. The effect of variation of the phosphine ligand has been studied using [RuC1[sub]2{(4-X-C[sub]6H[sub]4)[sub]3P}[sub]3] (where X=C1,H,Me and MeO) and a clear relationship between catalytic efficiency and the electronic nature of the ligand has been demonstrated for the reaction between oct-1-ene and CC1[sub]4.The relationship is more complex in the case of the analogous cyclohexene reactions which also displayed marked solvent effects, The reactions of both oct-1-ene, cyclohexene and CC1[sub]4 in the presence of [RuCl[sub]2(PPh[sub]3)[sub]3] have been studied in a wide range of solvents. The importance of solvent viscosity in determining yields in these radical reactions has been demonstrated. A preliminary study of the addition of CC1[sub]4 to cyclo-l,3-dienes was also made with specific emphasis on the investigation of the stereochemistry of the addition products. A study has also been made of the catalysedsynthesis of lactones by addition of trichloroacetic acid to alkenes in the presence of [RuC1[sub]2(PPh[sub]3)[sub]3]. The reaction has been extended to the synthesis of dibrominated lactones from tribromoacetic acid and alkenes. A method was developed for purification of the bromolactones, as they were found to be suseeptable to thermal decomposition.
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Lorusso, Patrizia. "Metal catalysed alkylation of carbonyl compounds with formaldehyde." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7823.
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Formaldehyde is a chemical used widely in the manufacture of building materials. A remarkable example is represented by the Lucite two-step Alpha technology for the large scale production of methyl methacrylate (MMA), the essential building block of all acrylic-based products. Esters and ketones are important intermediates in the manufacture of acrylate esters therefore α-hydroxymethylenation of carbonyl compounds using formaldehyde as a one carbon alkylating agent and subsequent dehydration to the corresponding methylenated derivatives has been explored in the current work. We report a novel catalytic approach for the synthesis of methyl methacrylate (MMA) via one-pot α-methylenation of methyl propanoate (a chemical intermediate of the ALPHA process) with formaldehyde, generated in situ by Ru-catalysed dehydrogenation of methanol. Elucidation of the mechanism involved in the catalytic dehydrogenation of methanol along with the collateral alcohol decarbonylation reaction was gained through a combined experimental and DFT study. The development of an alternative process where anhydrous formaldehyde is produced in situ would provide a simplification over the current second step of the ALPHA technology where the formaldehyde is initially produced as formalin, subsequently dehydrated to afford anhydrous formaldehyde in order to ensure high selectivity to MMA. As an alternative approach, ketones, in particular 3-pentanone and 2-butanone, were targeted as potential substrates in order to overcome some of the problems related to competing reactions that occur at the ester group. Hydroxymethylenation, followed by dehydration and Baeyer-Villager oxidation, possibly catalysed by enzymes to reverse the normal selectivity, leads to the formation of acrylate esters. The catalytic reaction is enabled by a gold carbene hydroxide complex in such a way that the substrate undergoes C-H activation and the nascent metal alkyl acts as a nucleophile towards the electrophilic formaldehyde, supplied in the form of alcoform* (solution of paraformaldehyde in methanol).
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Newton, Claire. "New approaches to asymmetric transition metal catalysed reactions." Université Louis Pasteur (Strasbourg) (1971-2008), 1995. http://www.theses.fr/1995STR13018.
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La premiere partie de ce travail decrit la synthese et la caracterisation de deux types de complexes d'iridium(+3) portant des ligands diphosphines et de formule generale ir(pp*)(l-l)hii et ir(pp*)(l-l)hi, ou l-l represente un ligand bidentate chelatant neutre (n-n, n-o, et pp*) ou anionique (n-o). Ces complexes possedent des centres metalliques stereogeniques. Grace a la presence de la diphosphine chirale, ces complexes existent sous la forme de deux diastereoisomeres. En variant les ligands chelatants, nous sommes arrives a changer les proportions relatives des diastereoisomeres et, dans un cas nous avons isole un seul diastereoisomere. Nous avons egalement examine l'activite de ces complexes comme catalyseurs dans la reaction d'hydrogenation enantioselective d'imines prochirales. La deuxieme partie de ce travail est consacree a la conception de nouveaux ligands mixtes tridentates de type p-n-p contenant deux fonctions phosphine, phosphinite ou phosphite liees a l'atome d'azote central. Dans le cas de la diphosphite, nous avons incorpore des substituants chiraux sur les deux phosphores afin d'obtenir un ligand chiral possedant une symetrie c-2. Cette serie de ligands peut se coordiner aux metaux de facon meridionale, permettant de maintenir la symetrie c-2 dans les complexes metalliques. Nous avons etudie la complexation de cette serie de ligands avec le rhodium(+1) et l'iridium(+1) et isole des complexes susceptibles d'etre actifs en catalyse homogene. Nous avons examine certains d'entre eux dans les reactions d'hydrogenation et d'hydroformylation catalytiques d'alcenes
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Dwivedi, Seema. "Green approaches towards transition-metal catalyzed and metal-free c - c and c - heteroatom coupling reactions." Thesis, University of North Bengal, 2019. http://ir.nbu.ac.in/handle/123456789/3646.
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Epton, Jeremy W. "Alkene hydroformylation catalysed by dinuclear rhodium complexes." Thesis, Kingston University, 1990. http://eprints.kingston.ac.uk/20536/.
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Hurtado, Rodrigo Cesar. "Novel transition metal-catalysed reactions of allenes and bisallenes." Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/59628/.
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The research in this thesis is focused on new intermolecular additions of diverse nucleophiles to allenic and bisallenic motifs catalysed by transition metals. In the first project we developed a new Au-catalysed azidation of allenes for the synthesis of functionalised allylic azides, which are important precursors to many functional groups. A cationic Au(I)-catalyst was found as a suitable activator for the allenic π-system favouring the attack of challenging azides as nucleophiles and giving access to the desired allylic azides. Deuterium-labelling experiments revealed that the reaction goes via a vinyl gold intermediate, which allowed an orthogonal functionalisation of the allenes, using as electrophile iodine to break the Au-C giving valuable iodo-alkenyl azides. Besides, preliminary mechanistic studies by NMR disclosed a possible inner-sphere mechanism with the formation of Au-N3 complexes with a continuous exchange of counterions involved in the reaction. The second part of the present thesis was aimed to develop a novel platinum-catalysed carbo- and heterocyclization of 1,5-bisallenes to obtain 6- or 7-membered rings with and extra oxygen functional group incorporated in the skeleton of the molecule. These cyclic compounds are interesting building blocks encountered into the core of several natural products, especially in terpene and sesquiterpene family. Cationic Pt(II)-catalysts with electron-withdrawing ligands were found appropriate to lead the ring closing of these 1,5-bisallenes. The reaction seems to be triggered by the attack of oxygen nucleophiles to the activated terminal π-system of the bisallene showing different coordination modes, which give access to isomeric 6- or 7-membered rings. Deuterium labelling and preliminary mechanistic experiments revealed, that the formation of the products goes via a vinyl platinum intermediate in the different cyclization modes. Besides, the reaction has been monitored by 1H NMR in order to study the decomposition level of the bisallenes under catalytic conditions and the possible interconversion between the isomeric cyclic products.
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Tosatti, Paolo. "Metal-catalysed asymmetric allylic substitution reactions for array synthesis." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540583.
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Sharma, Uma Devi. "Mechanistic studies on transition metal complex catalysed homogeneous hydrogenation." Thesis, University of Oxford, 1996. http://ora.ox.ac.uk/objects/uuid:946e1f34-d03a-4d67-8aa9-37a0794985cf.
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The development of systems capable of catalysing the reduction of unsaturated bonds with very high selectivities is one of the greatest successes of asymmetric catalysis. The mechanism by which rhodium complexes catalyse alkene hydrogenation has been effectively established through a combination of kinetic studies and isolation and characterisation of the intermediates in solution. It was hoped to elucidate the corresponding ruthenium catalysed mechanism using similar techniques. Following the synthesis of a selection of ruthenium catalysts, their activity towards the reduction of a selection of dehydroamino acid derivatives at ambient temperature and pressure was investigated. Having successfully tested out the activity of these catalysts, NMR studies were initiated in order to observe and characterise intermediates in the catalytic cycle. Considerable effort was put into the NMR studies, the systems were looked at under both argon and hydrogen, but although some substrate containing species were observed, it was found to be effectively impossible to break into the catalytic cycle and observe intermediate species using NMR techniques. Electrospray mass spectrometry investigations yielded more successful results, though still no hydrogen containing intermediates were observed. However, it was possible to make a detailed kinetic study of several ruthenium catalyst / substrate systems by looking at the dependence of reaction rate on classic variables such as hydrogen pressure, catalyst concentration and substrate concentration. The combined results of electrospray experiments, kinetic analyses and kinetic modelling using computer packages enabled a possible mechanistic pathway to be proposed.
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Barr, Darrin Alexander. "Metal catalysed cycloadditions of imines of #alpha#-amino esters." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334558.
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Harm, A. M. "Chiral ligands for asymmetric metal-catalysed additions to alkenes." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318258.
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Millington, Emma Louise. "Complex pyrrolidines via metal catalysed 1,3-dipolar cycloaddition reactions." Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400169.
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Albone, David P. "Metal-catalysed atom transfer to alkenes and activated hydrocarbons." Thesis, University of Warwick, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247415.
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Gazzard, Lewis John. "The preparation of enolates via metal catalysed allylic isomerisation." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339211.
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Wright, Andrew. "Spectroscopic and mechanistic studies of metal catalysed methanol carbonylation." Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250433.
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Qadir, Maryiam. "Transition-metal catalysed synthesis of medium-sized nitrogen heterocycles." Thesis, King's College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415464.
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Gouriou, Laure. "Mechanistic studies on metal catalysed asymmetric allylic alkylation reactions." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406956.
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Owston, Nathan Ashley. "Novel transition metal-catalysed syntheses of carboxylic acid derivatives." Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512253.
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This thesis describes the chemistry developed during a study of novel transition metalcatalysed reactions for the synthesis of carboxylic acid derivatives. Chapter 2 describes a novel protocol for the synthesis of primary amides from alcohols in one-pot where a metal complex mediates two fundamentally different catalytic processes. An iridium catalyst has been shown to be effective for the selective rearrangement of aldoximes into primary amides. In addition, an iridium-catalysed oxidation of activated alcohols via hydrogen transfer has been developed using an alkene as formal oxidant. These reactions have been combined in a sequential process affording good yields for a range of benzylic alcohols. An improved system for the rearrangement of aldoximes into amides using a new ruthenium catalyst is described in Chapter 3. Through a systematic program of optimisation excellent selectivity was achieved for a wide range of substrates at markedly reduced catalyst loading. Chapter 4 describes the development of a ruthenium-catalysed elimination reaction for the conversion of oxime ethers into nitriles. The application of this reaction to tandem and sequential reactions has been explored, albeit with limited success. Also, a method for the ruthenium-catalysed oxidation of alcohols using an electron-deficient alkene as hydrogen acceptor is described, and its application to a tandem oxidation process with a nitrogen nucleophile demonstrated. As an extension of the concept presented in Chapter 4, tandem oxidation processes with oxygen nucleophiles are the subject of Chapter 5. This strategy has been used for the oxidation of primary alcohols to their corresponding methyl esters in one-pot, with good yields obtained for a range of substrates. The use of water as a nucleophile in such a process has also been examined.
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Ellis, Peter Richard. "Reactions of unsaturated hydrocarbons catalysed by transition metal compounds." Thesis, Durham University, 1998. http://etheses.dur.ac.uk/4783/.
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A range of different heterogeneous catalysts for the isomerisation of ortho-xylene have been prepared and evaluated. These included commercially-available samples, supported metal catalysts and zirconia-based catalysts. The greatest activity was seen for the former, which was found also to be active for a number of related reactions. Zirconia-based catalysts, in particular sulphated zirconia, gave significant activity. It was possible to prepare a catalyst to give 9.5% conversion of ortho-xylene per gram of catalyst with good selectivity to the meta isomer. The catalyst was prepared in two ways, either by the action of ammonium sulphate on "zirconium hydroxide", a hydrated zirconia precursor, or by precipitation from a sulphuric acid-containing solution of zirconium (IV) propoxide. The factors in the synthesis procedure which affect the catalytic performance of the catalyst were investigated. These included choice of reagents, preparative method and calcination procedure. This information was used to prepare an 'idealised' catalyst, which showed activity for a number of reactions of commercial interest. A range of different aminophosphine complexes based on the reaction of a N,N'- substituted diamine with chlorodiphenylphosphine have been prepared for subsequent study as ligands in complexes active in homogeneous catalysis. Palladium and platinum complexes of the type [(diaminodiphosphine)MCl(_2)] have also been prepared and characterised. A number of x-ray diffraction analyses have been performed, which along with other data has allowed the solid state and solution structures to be discussed. The relative reactivities of the ligands have been determined by reactions with manganese pentacarbonyl bromide and also with palladium dichloride complexes. This depends largely on the steric requirements of the ligand in question. The potential of these ligands in catalysis has been evaluated by the performance of their platinum dichloride complexes in the tin (II)-promoted hydroformylation of styrene, and their palladium acetate complexes for the methoxycarbonylation of ethene.
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Franchino, Allegra. "New asymmetric metal-catalysed addition processes for amine synthesis." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:c8207684-596d-4fb8-b93e-292911b45b5d.
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This thesis concerns the development of novel catalytic approaches for the construction of stereocentres bearing a nitrogen atom. In 2011, the Dixon group reported a Ag(I)/cinchona-derived amino phosphine catalytic system for the activation of isocyanoacetates in asymmetric aldol and Mannich reactions. During this thesis work it was sought to extend the scope of this catalytic system to Mannich additions of other isocyanide pronucleophiles, then the focus was broadened to include Reformatsky and α-alkylation reactions of ketimine substrates. Chapter 1 gives an overview of the state of the art with particular emphasis on catalytic enantioselective additions to ketimines and the use of activated isocyanides as pronucleophiles. Chapter 2 describes the application of the Ag-catalysed enantio- and diastereoselective aldol reaction of isocyanoacetates to the concise asymmetric synthesis of the antibiotic chloramphenicol, which possesses a chiral stereodefined α-amino β-hydroxy motif. Chapter 3 details our efforts to expand the scope of the Ag(I)/amino phosphine catalytic system to the activation of more challenging isocyanides lacking an electron-withdrawing group in the α-position by investigating aldol and Mannich reactions of benzyl isocyanide. Chapter 4 describes how the scope of the Ag(I)/amino phosphine catalytic system was successfully extended to another pronucleophile, the versatile p-toluenesulfonylmethyl isocyanide (TosMIC). The first catalytic enantio- and diastereoselective addition of TosMIC to N-diphenylphosphinoyl (N-DPP) ketimines was developed, affording 2-imidazolines possessing two contiguous stereocentres with high yields and excellent levels of stereocontrol. Chapter 5 describes the development of a Ni(II)-catalysed Reformatsky reaction of N-DPP ketimines with ethyl bromoacetate and diethylzinc, providing racemic amines bearing a quaternary stereocentre in the α-position in good yields. Chapter 6 reports the serendipitous discovery of the α-alkylation of N-DPP ketimines with ethyl bromoacetate using visible light photoredox catalysis. The transformation, catalysed by ruthenium(II) and nickel(II) complexes under mild conditions, was optimised, its scope assessed and the mechanism investigated.
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Taylor, David J. "Metal catalysed transfer hydrogenation, dehydrogenation and racemisation of amines." Thesis, University of York, 2010. http://etheses.whiterose.ac.uk/1473/.
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This thesis describes the study of the fundamental mechanisms relating to asymmetric transfer hydrogenation (ATH) of imines and the transfer dehydrogenation and racemisation of secondary amines by Cp*Rh and Cp*Ir complexes. A series of 16-electron complex of the type Cp*M(XNC6H4NX’) (where M = Rh or Ir and X, X’ = H or Ts) have been synthesised, fully characterised and demonstrated to be active catalysts for the transfer hydrogenation of imines. The crystal structures of the complexes reveal structural features that are important in understanding their unique ability to act as transfer hydrogenation catalysts including a remarkable trend in the M-N bond lengths, indicative of M-NH π-bonding and the absence of M-NTs π-bonding which has several implications for catalysis. The complexes allowed catalytic studies without the need for 18-electron precursors, as is the case for the more widely used Noyori-type Cp*M(Cl)(TsNCHPhCHPhNH2) (where M = Rh or Ir) ATH complexes. We observed key intermediates in the mechanism by NMR spectroscopy such as an 18-electron formate complex, Cp*Rh(OCHO)(TsNC6H4NH2) and the 18-electron Rh(III) hydride complex, Cp*Rh(H)(TsNC6H4NH2). An 18-electron chloride precursor complex, Cp*Rh(Cl)(TsNC6H4NH2) was also characterised by X-ray crystallography. DFT calculations were used to support our observations and an “outer-sphere” mechanism for the transfer hydrogenation of imines is proposed. We also studied the mechanism of a dimeric Cp*Ir diiodide complex, [Cp*Ir(I)2]2 that is capable of amine racemisation under mild conditions and characterised several key intermediates including an ammine-coordinated complex, Cp*Ir(I)2(NH3) which itself was demonstrated to be equally active for the racemisation process under identical conditions; amine bound complexes of the type Cp*M(X)2(PhCH2NHMe) (where M = Rh, Ir and X = Cl, I) proposed to be the first step in the mechanism; an imine-coordinated Cp*Ir diiodide complex characterised by 1H/15N HSQC and the reversible hydrogenation of this complex by addition of molecular hydrogen to form the corresponding amine. A mechanism based on the current evidence for the racemisation of amines using the [Cp*Ir(I)2]2 catalyst is proposed. Finally, we describe a method for producing hyperpolarised carbon dioxide gas by using the Cp*Rh(Cl)(TsNCHPhCHPhNH2) ATH catalyst to catalytically decompose a pre-hyperpolarised solution of natural abundance formic acid, which was observed by 13C NMR spectroscopy.