Selective aza-Barbier Allylations of N-tert-Butanesulfinylimines

Significance

α-Methylene-γ-lactams are structural units occurring in a wide variety of biologically active natural products. Villiéras reported a strategy toward the diastereoselective synthesis of α-methylene-γ-lactams by reaction of chiral ­imines with β-functional crotylzinc reagents (V. Nyzam, C. Belaud, F. Zammattio, J. Villiéras Tetrahedron: Asymmetry 1996, 7, 1835). The authors have had previous experience in the selective allylation of N-sulfinylimines with organozinc reagents and recognized an opportunity to apply this metho­dology to the synthesis of these heterocycles (X.-W. Sun, M.-H. Xu, G.-Q. Lin Org. Lett. 2006, 8, 4979). An efficient and facile one-pot ­approach for the stereoselective synthesis of highly substituted lactams through aza-Barbier-type allylations of chiral sulfinylimines is realized.