Enantioselective Conjugate Addition to a,b-Unsaturated Esters and Amides Mediated by Lithium Perchlorate

An efficient method for the enantioselective 1,4-conjugate addition of amines to a,b-unsaturated esters containing an inexpensive chiral auxiliary, such as (S)-2-methyl-1-butanol and fenchyl alcohol, in solvent-free conditions mediated by solid lithium perchlorate is reported. Over 12 examples of the products are generated in excellent yields, accompanied by moderate enantioselectivity. The concentrated solution of LiClO4 in a diethyl ether system works well for the enantioselective 1,4-addition of organolithium compounds to a,b-unsaturated amides without any side reactions