Enantioselective Iridium-Catalyzed Cycloisomerization of N-Methylanilines

Key words

iridium catalysis - indolines - C–H functionalization

Significance

Isomerizations with high atom-economy are attractive strategies to generate complex frameworks from simpler starting materials. The authors use an enantioselective iridium-catalyzed cycloisomerization to obtain chiral indolines in good yields and excellent enantioselectivities. Mechanistic studies suggest that C–H bond oxidative addition was the rate-determining step.

Comment

The reaction was successful with a variety of aryl substituents on the aniline or pendant aryl ring including heteroaromatic aryl groups. The reaction scope was also broad, with various substituents on the nitrogen including removable benzyl groups. The reaction proceeded through a C–H oxidative addition followed by an enantioselective carboiridation and a reductive elimination.