Asymmetric Multicomponent Domino Reactions and Highly Enantioselective Conjugated Addition of Thiols to α,β-Unsaturated Aldehydes

An organocatalytic asymmetric multicomponent domino and a conjugated addition reaction to α,β-unsaturated aldehydes are presented. The development is based, first, on an organocatalyzed highly enantioselective nucleophilic thiol addition to the β-carbon atom in the iminium ion intermediate, followed by an electrophilic amination of the α-carbon atom to the enamine intermediate. The multicomponent reactions proceed to give enantiopure amino−thiols in moderate to good yields. Furthermore, the organocatalyzed thiol addition to α,β-unsaturated aldehydes takes place in good yields and excellent enantioselectivities.