Photoreactions of indoline-2-thiones with cyanoalkenes

Abstract

The photochemical reactions of Indoline-2-thiones with alkenes have been examined. Irradiation of Indoline-2-thiones (1) in the presence of cyano olefins (2) gave (E/Z)-2-alkylideneindolines (3) and (4) through ring cleavage of thietanes, which were formed by [2 + 2] photocycloaddition of thiocarbonyl and olefin. Aminothietane (6), hitherto unknown, was first isolated in the photoreaction of 1,3,3-trimethylindoline-2-thione (1a) with isobutene.