[2 + 2] Photocycloadditions between the Carbon-Nitrogen Double Bonds of Imines and Carbon-Carbon Double Bonds.

In contrast to the well-known [2 + 2] photocycloadditions between C═O and C═C bonds, the participation of C═N bonds in such reactions is relatively rare. In this paper, the unprecedented UV-light-induced [2 + 2] cycloadditions between N-arylsulfonylimines and styrene derivatives or benzofurans are described. This photolytic reaction allows the highly stereoselective construction of azetidine derivatives under ambient conditions.