Stereospecific Synthesis of 2‑Iminothiazolidines via Domino Ring-Opening Cyclization of Activated Aziridines with Aryl- and Alkyl Isothiocyanates

Lewis
acid catalyzed domino ring-opening cyclization of activated
aziridines with aryl and alkyl isothiocyanates has been accomplished
leading to the formation of a wide variety of highly substituted and
functionalized 2-iminothiazolidines with excellent diastereo- and
enantiospecificity (de, ee up to >99%). The reaction proceeds via
a Lewis acid catalyzed SN2-type ring-opening of the activated
aziridine followed by a concomitant 5-exo-dig cyclization
in a domino fashion to furnish the 2-iminothiazolidine derivative
in excellent yields (up to 99%).