20068-20-6Relevant articles and documents
Bidentate NHC-based chiral ligands for efficient Cu-catalyzed enantioselective allylic alkylations: Structure and activity of an air-stable chiral Cu complex
Larsen, Andrew O.,Leu, Wenhao,Oberhuber, Christina Nieto,Campbell, John E.,Hoveyda, Amir H.
, p. 11130 - 11131 (2004)
Cu-catalyzed addition of alkylzinc reagents to a range of allylic phosphates is promoted efficiently and with high enantioselectivity to afford tertiary as well as quaternary carbon centers (up to 98% ee). Reactions proceed to completion with 0.5-5 mol % catalyst loading and are best promoted by commercially available CuCl2·2H2O. The X-ray structure of the chiral NHC-Ag(I) complex used in the study as well as that of a catalytically active NHC-Cu(II) complex are also reported; both complexes are air-stable and are formed in ≥95% isolated yield. The isolated Cu complex, which can be handled in air, is catalytically active. The present report provides the first precedent for efficient Cu-catalyzed allylic alkylations with chiral NHC ligands. Copyright
Highly enantioselective copper-catalyzed allylic alkylation with atropos phosphoramidites bearing a D2-symmetric biphenyl backbone
Fang, Fang,Zhang, Hui,Xie, Fang,Yang, Guoqiang,Zhang, Wanbin
, p. 3593 - 3598 (2010)
A novel class of atropos dibridged biphenyl phosphoramidites bearing a D2-symmetric biphenyl backbone was prepared and applied as chiral ligands in the copper-catalyzed allylic alkylation with Grignard reagent. The alkylation products were obtained in quantitative yields with high regioselectivities up to 94:6 of SN2′/SN2 ratio and enantiomeric excesses up to 91.1% for SN2′ products. The unique D2-symmetric backbone ligands have the advantages of easy preparation and sufficient reusability of their key intermediates from the undesired isomers.
From Prochiral N-Heterocyclic Carbenes to Optically Pure Metal Complexes: New Opportunities in Asymmetric Catalysis
Kong, Lingyu,Morvan, Jennifer,Pichon, Delphine,Jean, Marion,Albalat, Muriel,Vives, Thomas,Colombel-Rouen, Sophie,Giorgi, Michel,Dorcet, Vincent,Roisnel, Thierry,Crévisy, Christophe,Nuel, Didier,Nava, Paola,Humbel, Stéphane,Vanthuyne, Nicolas,Mauduit, Marc,Clavier, Hervé
supporting information, p. 93 - 98 (2020/01/09)
Well-defined optically pure transition metal (TM) complexes bearing C1- and C2-symmetric N-heterocyclic carbene (NHC) ligands were prepared from prochiral NHC precursors. As predicted by DFT calculations, our strategy capitalizes on
Copper(i)-catalysed asymmetric allylic reductions with hydrosilanes
Thanh Nguyen,Thiel, Niklas O.,Teichert, Johannes F.
supporting information, p. 11686 - 11689 (2017/11/03)
A copper(i)-catalysed asymmetric allylic reduction enables a regio- and stereoselective transfer of a hydride nucleophile in an SN2′-fashion onto allylic bromides. This transformation represents a conceptually orthogonal approach to allylic substitution reactions with carbon nucleophiles. A copper(i) complex based upon a chiral N-heterocyclic carbene (NHC) ligand allows for stereoselectivity reaching 99% ee. The catalyst enables a stereoconvergent reaction irrespective of the double bond configuration of the starting materials.
Metal alkylidene complexes comprising an unsymmetrical unsaturated NHC ligand
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Paragraph 0141, (2015/01/18)
The present invention relates to metal alkylidene complex comprising a 1-aryl-3-alkyl-imidazol-2-ylidene ligand, wherein the aryl group of said 1-aryl-3-alkyl-imidazol-2-ylidene ligand is an aromatic and wherein the alkyl group of said 1-aryl-3-alkyl-imidazol-2-ylidene ligand is selected from the group consisting of a cyclic secondary aliphatic alkyl and a C2-C10-heteroalkyl, and wherein said metal is selected from the group consisting of Pd, Ag, Au, Ir, Rh, Cu, Ni, Mg, Zn, Ti, Pt and Fe, with the provision that the aryl group of said 1-aryl-3-alkyl-imidazol-2-ylidene ligand is other than an ortho-hydroxyaryl group when said metal is Pd and when said cyclic secondary aliphatic alkyl is cyclohexyl.
