An Asymmetric Alkynylation/Hydrothiolation Cascade: An Enantioselective Synthesis of Thiazolidine-2-imines from Imines, Acetylenes and Isothiocyanates.

A multicomponent reaction between imines, terminal alkynes, and isothiocyanates in the presence of a catalytic chiral copper–pybox complex proceeds enantioselectively to give enantiopure thiazolidine-2-imines (60–99% ee) via a highly regioselective intramolecular 5-exo-dig hydrothiolation reaction.