C2 Symmetric Chiral NHC Ligand for Asymmetric Quaternary Carbon Constructing Copper-Catalyzed Conjugate Addition of Grignard Reagents to 3-Substituted Cyclohexenones
- 20 May 2008
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 73 (12) , 4578-4581
- https://doi.org/10.1021/jo800613h
Abstract
The asymmetric construction of quaternary carbon centers by conjugate addition of Grignard reagents to 3-methyl- and 3-ethylcyclohexenones was realized in a maximum enantioselectivity of 80% by using a C2 symmetric chiral N-heterocyclic carbene (NHC)-copper catalyst, generated from (4S,5S)-1,3-bis(2-methoxyphenyl)-4,5-diphenyl-4,5-dihydro-1H-imidazol-3-ium tetrafluoroborate and copper(II) triflate. The stereostructures of the NHC-Au complexes were analyzed by X-ray crystallography, which rationalized the good stereocontrolling ability of N-aryl NHCs.Keywords
This publication has 43 references indexed in Scilit:
- Recent Advances in Metal-Catalyzed Asymmetric Conjugate AdditionsSynthesis, 2007
- Asymmetric Synthesis of Intermediates for Otamixaban and Premafloxacin by the Chiral Ligand-Controlled Asymmetric Conjugate Addition of a Lithium AmideThe Journal of Organic Chemistry, 2006
- Catalytic Asymmetric Conjugate Addition of Dialkylzinc Reagents to β-Aryl-α,β-unsaturated N-2,4,6-Triisopropylphenylsulfonylaldimines with Use of N-Boc-l-Val-Connected Amidophosphane-Copper(I) CatalystThe Journal of Organic Chemistry, 2004
- Chiral Ligand-Controlled Asymmetric Conjugate Addition of Lithium Amides to EnoatesJournal of the American Chemical Society, 2003
- Chiral amidomonophosphine-rhodium(I) catalyst for asymmetric 1,4-addition of arylboronic acids to cycloalkenonesTetrahedron Letters, 2001
- A Ternary Complex Reagent for an Asymmetric Reaction of Lithium Ester Enolates with IminesJournal of the American Chemical Society, 1997
- Asymmetric conjugate addition of organomagnesium cuprates controlled by a stoichiometric amount of chiral phosphineTetrahedron Letters, 1995
- Enantioselective conjugate addition of organocuprate using a chiral amidophosphine ligandTetrahedron Letters, 1992
- Asymmetric Synthesis Utilizing External Chiral LigandsSynthesis, 1990
- Novel strategy of using a C2 symmetric chiral diether in the enantioselective conjugate addition of an organolithium to an .alpha.,.beta.-unsaturated aldimineJournal of the American Chemical Society, 1989