TADDOL-based phosphane-phosphite ligands in enantioselective Cu-catalyzed Grignard 1,4-additions followed by mannich-type alkylations

Abstract

Copper(I) complexes of TADDOL-based phosphane-phosphite ligands catalyze enantioselective conjugate additions of various Grignard reagents to cyclic enones. Through trapping of the resulting chiral magnesium enolates with N-benzylidene-4-methylbenzenesulfonamide (as an imine) in one-pot procedures, the corresponding Mannich products (i.e., β-aminocarbonyl compounds) were obtained in good yields and high enantiomeric purities, although with only low diastereoselectivities. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.