Chiral N,N-Dialkylnorephedrines as Catalysts of the Highly Enantioselective Addition of Dialkylzincs to Aliphatic and Aromatic Aldehydes. The Asymmetric Synthesis of Secondary Aliphatic and Aromatic Alcohols of High Optical Purity

Article abstract of DOI:10.1021/jo00013a035

The chiral N,N-dialkylnorephedrine-catalyzed addition of dialkylzincs to aliphatic and aromatic aldehydes afforded secondary alcohols of high optical purity (to > 95percent ee).Among the N,N-di(primary alkyl)norephedrines, N,N-di-n-butylnorephedrine (DBNE, 3d) was found to be the most effective catalyst. 1-Phenyl-2-(1-pyrrolidinyl)propan-1-ol (3i) and N,N-diallylnorephedrine (3j) were also highly effective catalysts.The method described provides optically active secondary aliphatic alcohols of high optical purity which cannot be prepared by conventional methods.