Novel one-pot asymmetric cascade approach toward densely substituted enantioenriched α-methylene-γ-lactams

A novel one-pot asymmetric synthesis of densely substituted α-methylene-γ-lactams in favor of cis-isomer involving Zn-promoted aza-Barbier-type reaction has been well established. A wide array of α-methylene-γ-lactams were obtained in high yields with excellent diastereomeric ratios from 98:2 to >99:1 and good enantioselectivities. The synthetic potential of such α-methylene-γ-lactams was demonstrated by successfully oxidizing the phenol moiety to quinone in quantitative yield.