Asymmetric additions using diorganozincs

Abstract

Abstract Enantioselective additions of organometallic reagents to carbonyl compounds (1,2-addition to aldehydes and 1,4-addition to enones) and imines are important methods for the preparation of optically active sec-alcohols, 13-substituted ketones, and amines, respectively. The reactivities of diorganozincs toward the additions to carbonyl compounds and imines are usually much lower than those of the corresponding organolithium and organomagnesium reagents. Without any catalyst, diorganozincs do not usually add to aldehydes and imines in synthetically useful yields. However, owing to the low reactivities of diorganozincs, the catalytic enantioselective additions of diorganozincs to aldehydes, enones, and imines have become possible by using either chiral Lewis acids or Lewis bases as chiral catalysts.