Catalytic asymmetric cross-coupling

Asymmetric cross-coupling of secondary alkylmagnesium and -zinc reagents with aryl and alkenyl halides in the presence of nickel or palladium catalysts coordinated with chiral phosphine ligands give optically active cross-coupling products, This asymmetric cross-coupling is applied to the asymmetric synthesis of chiral allylic silanes (95% ee). Axially chiral biaryls are prepared by asymmetric cross-coupling between two aryl groups (95% ee) or by enantioposition-selective cross-coupling (99% ee). (C) 2002 Elsevier Science B.V. All rights reserved.