Academic literature on the topic 'Nickel complexes and Michael addition'

Rhodium-catalysed enantioselective allylation reaction of imines in the presence of chiral diene ligands has been investigated. Under the optimised conditions, cyclic imines provided homoallylic amines in high yield and excellent enantioselectivities. The reaction most likely proceeds via allylrhodium(I) intermediates, and represents the first rhodium-catalysed enantioselective nucleophilic allylation of π-electrophiles with allylboron compounds. Furthermore, the allylations display a strong preference for carbon–carbon bond formation at the more substituted terminus of the allyl fragment of the allyltrifluoroborate. To demonstrate the utility of the allylation products, representative manipulations were conducted. Enantioselective Nickel-Catalysed Michael Additions of 2-Acetylazaarenes to Nitroalkenes An enantioselective Michael addition of acylazaarenes with α-substituted β-nitroacrylates in the presence of a chiral Ni(II)–bis(oxazoline) complexes has been developed. A range of azaaryl nucleophiles were shown to react with a variety of nitroalkenes to construct highly functionalised Michael addition products which contain a stereogenic all-carbon quaternary stereocentre with moderate to high yields and enantioselectivities. A possible mechanism for this reaction has been proposed.

Ces travaux s’articulent autour de dérivés saccharidiques de type exo-glycals ou C-glycosides pour lesquels de nouvelles méthodologies synthétiques ainsi que des applications dans le domaine de la biologie ont été développées. Dans un premier temps, l’addition de nucléophiles soufrés et carbonés sur le carbone anomérique de différents exo-glycals activés a été réalisée, permettant un accès efficace à de nouveaux S-glycosides tertiaires ainsi qu’à des γ-glycoamino acides anomériques. Ces derniers ont été utilisés pour l’élaboration de peptides linéaires mixtes α/γ dont les propriétés de structuration ont ensuite été étudiées par RMN, IR, CD et modélisation moléculaire. De nouvelles plates-formes glycopeptidiques multifonctionnelles ont été préparées par cyclisation de ces peptides. Dans un second temps, le développement de peptidomimétiques ciblant le récepteur neuropiline-1, impliqué dans l’angiogenèse tumorale, a été entrepris. En s’appuyant sur des études de modélisation moléculaire, certains composés ont montré une bonne affinité pour le récepteur NRP-1 et l’un des composés a montré des propriétés prometteuses pour l’inhibition de la formation de tubules<br>This work is focused on the development of new synthetic pathways for exo-glycals functionalization and synthesis of bioactive compounds. The first part of this manuscript describes the efficient preparation of new tertiary S-glycosides and γ-glycoamino acids via Michael addition of thiols derivatives and carbanions on anomeric carbon of exo-glycals. The obtained γ-glycoamino acids were then incorporated in α/γ mixed peptides and their structural properties were studied by NMR, IR, CD and molecular modelling studies. Furthermore, cyclic multivalent platforms were built by intramolecular cyclization of these entities. The second part of the manuscript concerns the elaboration of peptidomimetics targeting neuropilin-1 receptor, implicated in tumor angiogenesis. Based on molecular modeling studies, some compounds showed interesting binding affinity for NRP-1 receptor and one of them displayed promising properties toward inhibition of tubule formation

Ce travail de thèse est dédié au développement des deux familles de complexes chiraux binaphtolates de terres rares et leur application en catalyse asymétrique dans les réactions d’addition de Michael, de Henry, de Strecker et d’hydroalkoxylation. La préparation d’une nouvelle famille de complexes chiraux bisbinaphtolates de terres rares a été optimisée. Ces nouveaux complexes ont été entièrement caractérisés grâce à des analyses RMN, IR, de spectroscopie de masse et des études de DRX de monocristaux isolés. Après une étude de stabilité, nous avons pu montrer que ces nouveaux complexes de terres rares peuvent être pesés à l’air libre et utilisés dans des réactions asymétriques sans dégazage des réactifs ni des solvants. Les comportements catalytiques de ces nouveaux complexes hétérobimétalliques ont été étudiés en détail dans des réactions énantiosélectives de Henry, de Strecker et d’addition de Michael. Une température d’isoinversion et un effet non linéaire ont notamment été mis en évidence dans la réaction d’addition de Michael de malonates sur des énones conduisant à des produits énantioenrichis avec des excès énantiomériques allant jusqu’à 83%. Une seconde famille de complexes monobinaphtolate monoalkyl de terres rares a été synthétisée et complètement caractérisée. Une structure DRX de ce type de complexe a pu être obtenue pour la première fois. Ces complexes ont été évalués dans des réactions de Strecker et d’hydroalkoxylation. Concernant cette dernière, la sélectivité a tout d’abord été étudiée avec ces complexes dans le cas des allènes et un mécanisme a pu être proposé. D’autre part, les premiers exemples d’hydroalkoxylation asymétrique d’alcènes, catalysés par ces complexes monobinaphtolate monoalkyl de terres rares, ont pu être décrits<br>This thesis is mainly devoted to the development of two families of rare earths chiral binaphtolate complex and their application in asymmetric catalysis such as Michael addition, Henry reaction, Strecker reaction and hydroalkoxylation reaction. At first, the preparation of a new family of rare earth bisbinaphtolate complexes has been optimized with complete characterizations including NMR, IR, mass spectroscopy and XRD studies on isolated single crystals. These new rare earths complexes are relative stable which can be used under air condition. The catalytic behavior of these new heterobimetallic complexes have been studied in detail: an isoinversion temperature was determined and the nonlinear effect was observed for asymmetric Michael additions of malonates on enones wich lead products with enantiomeric excess up to 83%. Secondly, a family of rare earth monobinaphtolate monoalkyl complexs has been synthesized and characterized. The first XRD structure of this family of complex was obtained. Steric substitutions of binaphtolate ligands on position 3,3’ have been proven to be essential for the formation of these complex. The selectivity of reaction of hydroalkoxylation of allene was studied with a proposed mechanism. First examples of asymmetric hydroalkoxylation of alkene catalyzed by rare earth complexes have been achieved by our rare earth monoalkyl monobinaphtolate complex

<p>The kinetic and mechanistic features of a new series ofplatinum-thallium cyano compounds containing a direct andunsupported by ligands metal-metal bond have been studied insolution, using standard mix–and–measurespectrophotometric technique and stopped–flow method.These reactions are interpreted as oxidative addition of the cspecies to the square planar Pt(CN)₄^2-complex. Each of these processes was found to befirst-order in Pt(CN)₄^2-, the corresponding TI^IIIcomplex and a cyanide ion donating species whichacts as a catalyst. Both di- and trinuclear complexes werestudied, and the kinetically significant thallium complexes intheir formation and the catalytically active cyanide sourcesare as follows: [(CN)₅PtTl(CN)₃]^3-: Tl(CN)₄^–(alkaline region), Tl(CN)₃(slightly acidic region) and CN^–; [(CN)₅Pt–Tl(CN)]–: Tl(CN)₂⁺and Tl(CN)₂⁺; [(CN)₅Pt–Tl–Pt(CN)₅]^3-: [(CN)₅Pt–Tl(CN)]–and HCN. Appropriatemechanisms were postulated for the overall reactions in allcases, which include i) metal–metal bond formation stepand ii) coordination of an axial cyanide ion to the platinumcenter. Two experimentally indistinguishable kinetic modelswere proposed for the formation of the dinuclear complexeswhich are different in the sequence of the two steps. In thecase of the trinuclear complex, experimental evidence isavailable to exclude one of the alternative reaction paths, andit was proven that the metal–metal bond formation precedesthe axial cyanide coordination.</p><p>The cyanide ligands coordinated to TI^IIIin the Pt–Tl complexes could be replacedsuccessfully with aminopolycarboxylates e.g.: mimda^2-, nta^3-, edta^4-. The [(CN)₅Pt–Tl(edta)]^4-complex, with a direct metal–metal bond hasbeen prepared in solution by two different reactions: a)dissolution of [(CN)₅Pt–Tl](s) in an aqueous solution of edta, b)directly from Pt(CN)₄^2-and Tl(edta)(CN)^2-. The decomposition reaction is greatlyaccelerated by cyanide and significantly inhibited by edta. Itproceeds through the [(CN)₅Pt–Tl(CN)₃]^3-intermediate. The formation of [(CN)₅Pt–Tl(edta)]^4-can proceed via two different pathways dependingon the ratio of the cyanide to the edta ligand concentrations.The’direct path’at excess of edta means theformation of intermediate[(CN)4Pt···Tl(CN)(edta)]^4-, followed by a release of the cyanide from theTl–centre followed by coordination of a cyanide from thebulk to the Pt–centre of the intermediate. The’indirect path’dominates in the absence of extraedta and the formation of the Pt–Tl bond occours betweenPt(CN)₄^2-and Tl(CN)4^–.</p><p>Homoligand MTl(CN)₄(M = Tl^I, K, Na) and, for the first time, Tl(CN)₃species have been synthesized in the solid stateand their structures solved by single crystal X–raydiffraction method. Interesting redox processes have been foundbetween TI^IIIand CN^–in non–aqueous solution and in Tl₂O₃-CN^–aqueous suspension. In the crystal structureof Tl(CN)₃·H₂O, the thallium(III) ion has a trigonal bypiramidalcoordination geometry with three cyanides in the trigonalplane, while an oxygen atom of the water molecule and anitrogen atom from a cyanide ligand attached to a neighboringthallium complex, form a linear O–Tl–N fragment.Cyanide ligand bridges thallium units forming an infinitezigzag chain structure. Among the thallium(III) tetracyanocompounds, the isostructural M[Tl(CN)₄](M = Tl and K) and Na[Tl(CN)₄]·3H₂O crystallize in different crystal systems, but thethallium(III) ion has in all cases the same tetrahedralgeometry in the [Tl(CN)₄]^–unit.</p><p>Three adducts of mercury(II) (isoelectronic with TI^III) (K₂PtHg(CN)₆·2H₂O, Na₂PdHg(CN)₆·2H₂O and K₂NiHg(CN)₆·2H₂O) have been prepared from Hg(CN)₂and square planar transition metal cyanides M^II(CN)₄^2-and their structure have been studied by singlecrystal X–ray diffraction, XPS and Raman spectroscopy inthe solid state. The structure of (K₂PtHg(CN)₆·2H₂O consists of strictly linear one dimensional wireswith Pt^IIand Hg^IIcenters located alternately, d_Hg–Pt= 3.460 Å. The structure of Na₂PdHg(CN)₆·2H₂O and K₂NiHg(CN)₆·2H₂O can be considered as double salts, the lack ofhetero–metallophilic interaction between both the Hg^IIand Pd^IIatoms, d_Hg–Pd= 4.92 Å, and Hg^IIand Ni^IIatoms, d_Ni–Pd= 4.60 Å, seems obvious. Electronbinding energy values of the metallic centers measured by XPSshow that there is no electron transfer between the metal ionsin all three adducts. In solution, experimental findingsclearly indicate the lack of metal–metal bond formation inall studied Hg^II–CN^-–M^II(CN)4^2-systems (M = Pt, Pd and Ni). It is in contrary tothe platinum–thallium bonded cyanides.</p><p><b>KEYWORDS:</b>metal–metal bond, platinum, thallium,kinetics, mechanism, stopped flow, oxidative addition, cyanocomplexes, edta, redox reaction, metal cyanides, X–raydiffraction, Raman, NMR, mercury, palladium, nickel, onedimensional wire</p>

博士<br>國立臺灣師範大學<br>化學系<br>101<br>Nickel-containing superoxide dismutase (NiSOD), has been discovered recently from Streptomyces species and marine cyanobacteria. NiSOD can catalyze the dismutation of O2− into O2 and H2O2 through a cycle of Ni(II) and Ni(III) oxidation states. In order to mimic the fuction of the active site of the NiSOD, a series of pentadentate ligands equipped with pyridine and proline derivatives have been designed and prepared. The prepared ligand, for instance 2,6-bis(((S)-2-(diphenylhydroxymethyl)-1-pyrrolidinyl)methyl)pyridine (H2BDPP), was deprotonated and employed to react with [Ni(CH3CN)6](ClO4)2 to give fivecoordinate Ni(BDPP) (5). Complex 5 can be readily oxidized by [Cp2Fe]PF6 at room temperature to form a stable Ni(III) complex, [Ni(BDPP)](PF6) (6). Complexes 5 and 6 were characterized by UV/vis spectroscopy, X-ray crystallography and cyclic voltammetry. Importantly, complex 6 can oxidized O2− to form O2, and its EPR spectrum is similar to that of the oxidaized form of NiSOD. In addition, direct reaction of H2BDPP reacted with Ni(BF4)2 and t-butylisocyanide gave six-coordinate [Ni(H2BDPP)(tBuNC)](BF4)2 (7), which exhibited the function of NiSOD. The reaction of 7 with KO2 released O2 gas, detected by GC, and generated H2O2, confirmed by peroxide test paper, peroxide indicator (LCV) and NMR spectroscopy.To enhance the water solubility and the electron donating ability of the NiSOD mimics, we designed and synthesized complexes 10, 11 and 14 with a hydroxy or methoxytriglycol (OTEG) group on the 4-position of pyrrolidine, and complexes 12 and 13 with a methoxyl and trimethylsilyl group on the para-position of four phenyl rings, respectively. On the other hand, two complexes, [Ni(BMePP)(CH3CN)](ClO4)2(15) and [Ni(BiPrPP)(CH3CN)](ClO4)(BPh4) (16) were synthesized (where BRPP =2,6-bis(((S)-2-(alkyloxycarbonyl)-1-pyrrolidinyl)methyl)pyridine), Me = methyl, iPr= isopropyl), and they can be employed as a catalyst for thia-Michael addition of thiols to α,β-enones. Notably, complex 15 possesses an excellent catalytic ability for thia-Michael reaction and gives good yields for 1,4-adducts.

Résumé: Dans le but de préparer des complexes de Zr pour la catalyse homogène de la polymérisation des lactides et de l’hydroamination des olefines, l’elaboration et l’optimisation d’une méthode systématique et efficace de synthèse des ligands dikétimines ayant différents substituants alkyles (R) à la position N,N’ a été realisée. Des dikétimines (nacnacRH) symétriques ont été obtenus avec une pureté de plus de 95 % et un rendement de 65 % lorsque R = Me et des rendements allant de 80 à 95 % lorsque le groupe R = n-Pr, i-Pr, i-Bu, Bu, Cy et (+)-CH(Me)Ph. La synthèse des dikétimines ayant des substituants N-alkyls différents, dite asymétriques, donne toujours un mélange statistique de trois ligands: nacnacR,R’H, nacnacR,RH et nacnacR’,R’H qui n’ont pu être separés. Seuls les dikétimines asymétriques avec un substituant N-alkyl et un autre N-aryl (nacnacR,ArH) ont été obtenus avec des rendements plus élevés que celui du mélange statistique. Par la suite, la complexation de ces ligands bidentés au Zr, la caractérisation de ces complexes et l’investigation de la réactivité ont été étudiés. Les complexes de Zr de type (nacnacR)2ZrCl2 ont été obtenus par deux voies de synthèse principales: la première consiste à traiter le sel de lithium du ligand avec le ZrCl4. La seconde est la réaction du ligand avec les complexes neutres d’alkyl-zirconium(IV) par protonation de l'alkyle coordonné. En solution, les complexes obtenus de (nacnacR)2ZrX2 possèdent un comportement dynamique via un « Bailar-twist » et les paramètres d'activation de cette isomérisation ont été calculés. Le complexe octaèdrique (nacnacBn)2ZrCl2 n'est pas réactif dans la carbozirconation et son alkylation n'était pas possible par l’échange des chlorures avec les alkyles. L’analogue diméthylé (nacnacBn)2ZrMe2 peut être préparé par alkylation du ZrCl4 avant la complexation du ligand. On a également observé que ce dernier n’est pas réactif dans la carbozirconation. L‘analogue diéthoxyde (nacnacBn)2Zr(OEt)2 est obtenu par échange des diméthyles avec les éthoxydes. La polymérisation du lactide avec celui-ci en tant que précurseur est relativement lente et ne peut être effectuée que dans le monomère fondu. Par conséquent, pour résoudre les problèmes rencontrés avec les complexes de zirconium (dikétiminates non-pontés), un ligand dikétimines pontés par le diaminocyclohexane, (±)-C6H10(nacnacXylH)2, LH2, (Xyl = 2,6-diméthylphényle) a été préparé. La complexation de ce ligand tetradenté au metal a été réalisée par deux voies de synthèse; la première est la réaction du sel de lithium de ce ligand avec le ZrCl4(THF)2. La deuxième est la déprotonation du ligand neutre avec le Zr(NMe2)4 et l’élimination du diméthylamine. Des complexes du type: (±)-C6H10(nacnacXylH)2ZrX2 avec X = Cl, NMe2 ont été obtenus. Les ligands de chlorure sont dans ce cas facilement remplaçables par des éthoxydes ou des méthyles. On a observé l’activité la plus élevée jamais observée pour un complexe d’un métal du groupe 4 avec le complexe de (±)-C6H10(nacnacXylH)2Zr(OEt)2 dans la polymérisation de lactide. L'étude cinétique a montré que la loi de vitesse est du premier ordre en catalyseur et en monomère et la constante de vitesse est k = 14 (1) L mol-1 s-1. L'analyse des polymères a montré l’obtention de masses moléculaires faibles et l’abscence de stéréocontrôle. La réaction de (±)-C6H10(nacnacXylH)2ZrCl2 avec le triflate d’argent donne le (±)-C6H10(nacnacXylH)2Zr(OTf)2. Le complexe bis-triflate obtenu possède une activité catalytique elevée pour les additions du type aza-Michael. L’utilisation du R,R-C6H10(nacnacXylH)2Zr(OTf)2 énantiopur comme catalyseur, dans les additions du type aza-Michael asymétriques donne le produit desiré avec un excès énantiomérique de 19%.<br>Abstract: In order to prepare the complexes of Zr targeted for homogeneous catalysis in polymerization of lactides and hydroamination of activated olefins, we focused on the elaboration and the optimization of a systematic and efficient method for the synthesis of diketimines ligands with a variety of substituted alkyl (R) on their position N,N'. Symmetrical diketimines (nacnacRH) were obtained with a greater than 95% purity and a yield of 65% when R = Me and yields ranging from 80 to 95% when R = nPr, iPr, iBu, Bn, and Cy (+)-CH (Me) Ph. The Synthesis of diketimines with different N-alkyl substituents, called asymmetric, always gives a statistical mixture of three ligands: nacnacR,R'H nacnacR,RH and nacnacR',R'H that made their isolation problematic. Yields greater than statistical mixtures were obtained only with asymmetric diketimines bearing N-alky and N-aryl substituents (nacnacR,ArH). Subsequently, we studied the complexation of these bidentate ligands with Zr, the characterization of these complexes and investigation of their reactivity. Zr complexes of type (nacnacRH)2ZrCl2 were obtained via two main synthetic routes: the first consists in treatment of the lithium salt of the ligand with ZrCl4. The second is the reaction of the ligand with neutral complexes of alkyl-zirconium (IV) by protonation of the alkyl coordinated. In solution, the obtained complexes (nacnacR)2ZrX2 showed dynamic behavior via a "Bailar-twist" isomerization and the activation parameters of the isomerization were calculated. Octahedral complex (nacnacBn)2ZrCl2, showed no reactivity in alkylation and carbozirconation was not possible by the exchange of alkyl with chlorides. The dimethyl analogue (nacnacBn)2ZrMe2, can be prepared by alkylation of ZrCl4 before ligand complexing. The diethoxide analogue (nacnacBn)2Zr(OEt)2 is obtained by exchange of dimethyls with ethoxides. The latter had slow reactivity in lactide polymerization under melt conditions. Consequently, to address the problems encountered with unbridged (diketiminate) zirconium complexes, a cyclohexanediyl-bridged diketiminate ligand, (±)-C6H10(nacnacXylH)2, LH2, (Xyl = 2,6-dimethylphenyl) is prepared. Complexation of the tetradentate ligand is realized via two synthetic routes; The first is reaction of the lithium salt of the ligand with ZrCl4(THF)2. The second is deprotonation of the neutral ligand with Zr(NMe2)4 and elimination of dimethylamine. Complexes of the type: (±)-C6H10(nacnacXylH)2ZrX2 with X = Cl, NMe2 are obtained. The chloride ligands are in this case readily replaceable with ethoxides or methyls. The (±)-C6H10(nacnacXylH)2Zr(OEt)2 complex showed the highest activity ever observed for any group 4 metal complex in lactide polymerization. The kinetic study showed that the rate law is first order in catalyst and monomer and the rate constant is k = 14(1) L mol−1 s−1. Analysis of the obtained polymer showed low molecular weight with no-stereocontrol. Reaction of the (±)-C6H10(nacnacXylH)2ZrCl2 with silver triflates yielded the (±)-C6H10(nacnacXylH)2Zr(OTf)2. The obtained bis-triflate complex showed to be a highly active catalyst for aza-Michael additions. The use of the enatiopure R,R-C6H10(nacnacXyl)2Zr(OTf)2 as catalyst for asymmetric aza-Michael additions of activated olefines gave the desired product with an enantiomeric excess of 19%.