Stereospecific Synthesis of 1,4,5,6-Tetrahydropyrimidines via Domino Ring-Opening Cyclization of Activated Aziridines with α-Acidic Isocyanides.

An expeditious synthetic route to access structurally diverse 1,4,5,6-tetrahydropyrimidines via domino ring-opening cyclization of activated aziridines with α-acidic isocyanides has been established. The transformation proceeds via Lewis acid mediated SN2-type ring opening of activated aziridines with α-carbanion of the isocyanides followed by a concomitant 6- endo- dig cyclization in a domino fashion to furnish the 1,4,5,6-tetrahydropyrimidine derivatives in excellent yields (up to 84%) and also in diastereo- and enantiomerically pure form (dr >99:1, ee >99%).