Enantiospecific Aluminum-Catalyzed (3+2) Cycloaddition of Unactivated Aziridines with Isothiocyanates

An Al(salen)Cl efficiently catalyzed the enantiospecific (3+2) cycloaddition of unactivated chiral aziridines with isothiocyanates to furnish functionalized iminothiazolidines at room temperature with 94–99% ee. The use of an aluminum Lewis acid as the catalyst, high enantiomeric purities, mild reaction conditions, broad substrate scope, and the high atom economy are the significant practical features.