SET-oxidative photocyclization reactions of N-(α-trimethylsilyl)-N-phenylglycinates with N-substituted maleimides: a role of silyl group in photocyclization

Abstract

SET-promoted photocyclization reactions of N-(α-trimethylsilyl)-N-phenylglycinates with N-substituted maleimides were explored using methylene blue (MB) as a photosensitizer, and mechanistic studies were performed. In contrast to the non-silylated N-phenylglycinate substrates, which showed no reactivity with maleimides, the MB-photosensitized reactions of N-(α-trimethylsilyl)-N-phenylglycinates with maleimides led to the formation of tetrahydroquinoline derivatives efficiently. These observations reveal that the silyl group adjacent to the nitrogen atom plays a crucial role in enabling a successful SET-oxidative cyclization reaction. Overall, this reaction protocol can expand the range of amine substrates in the diverse SET-oxidative photochemical reactions.