A new functionalized chiral disulfide derived from L-cysteine: (R,R)-bis[3-benzyloxazolan-4-yl)-methane] disulfide as a catalyst in the diethylzinc addition to aldehydes

摘要

A new, easily accessible, chiral disulfide 3 was prepared from L-cysteine in a short synthetic sequence (Scheme 1) and applied successfully as a highly efficient catalyst for the enantioselective addition of diethyl zinc to aromatic and aliphatic aldehydes to afford the product alcohols in up to more than 99% ee. In contrast to the more common amino alcohols used in similar reactions, catalyst 3 does not have a protic hydrogen in the form of a free hydroxy group.