The preparation of nonracemic secondary α-(carbamoyloxy)alkylzinc and copper reagents.: A versatile approach to enantioenriched alcohols

GRAPHICS Chiral alpha-(carbamoyloxy)alkyllithium reagents, prepared using Hoppe's sBuLi/(-)-sparteine methodology, were transmetalated with ZnCl2. Further transmetalation with CuCN with overall retention of configuration gave chiral species that reacted with various electrophiles to give enantiomerically pure alcohols after deprotection. A short, highly efficient synthesis of an industrially relevant pheromone, japonilure, illustrates the value of the methodology.