Visible-Light-Induced Iminothiolation of Unactivated Alkenes

An efficient visible-light-induced iminothiolation of unactivated alkenes has been developed for the rapid construction of pyrroline derivatives bearing a thioether moiety. In the presence of fac-Ir(ppy)₃ as photoredox catalyst, the acyl oximes were readily converted into iminyl radicals by single electron reduction under white LEDs irradiation, and the following radical cascading intramolecular cyclization and thioetherification would afford the functionalized pyrrolines with high efficiency. The mild reaction conditions including air atmosphere and ambient temperature allow for broad functional group tolerance. In addition, the good compatibility and practicality of this protocol is further highlighted by the employment of easily available thiophenols as the sulfur source for the thiolation process.