Substituted <i>N</i>-Salicylidene β-Aminoalcohols: Preparation and use as Chiral Ligands in Enantioselective Sulfoxidation and Conjugate Addition

Abstract

A high yielding synthesis of optically active 3,5-disubstituted salicylidene β-amino alcohols (6) is described. The catalytic use of D or L- N-(3-phenyl-5-nitrosalicylidene)valinol in enantioselective sulfoxidation (H 2 O 2 / VO(acac) 2 ) gives up to 95% e.e. Asymmetric conjugate addition of thiophenol to 2-cyclohexen-1-one catalysed by Ti(OPr- i) 4 and 6 leads to maximum 31% e.e. in the product.