Phosphine-Catalyzed Asymmetric Tandem Isomerization/Annulation of Allyl Amines with Allenoates: Enantioselective Annulation of a Saturated C-N Bond.

Under catalysis by chiral phosphine, an asymmetric isomerization/annulation cascade reaction of allylamines with allenoates was realized. A wide range of γ-substituted allenoates were tolerated to afford chiral pyrroline derivatives in high yields with excellent enantioselectivities. In the reaction, isomerization of readily available N-allylamines to reactive aliphatic imines through a 1,4-proton shift is a key step, which circumvents the isolation of highly unstable alkyl N-sulfonylimines.