Copper(II)-Catalyzed Asymmetric (3+3) Annulation of Diaziridines with Oxiranes.

Highly asymmetric (3+3) annulation of diaziridines with oxiranes via C-N bond cleavage in diaziridine was achieved under 10 mol % of chiral copper(II) complex as the catalyst under mild reaction conditions. With Cu(OTf)2 as the Lewis acid and C1-symmetric imidazolidine-pyrroloimidazolone pyridine as the ligand, diverse tetrahydro-[1,3,4]-oxadiazines were obtained by stereospecific C-N/C-O bond formation in moderate to good yields (up to 93% yield) and high diastereo- (>20:1 dr) and enantioselectivities (up to 92% ee). The catalytic cycle and stereochemical model were proposed by DFT calculation.