Redox‐Neutral TEMPO Catalysis: Direct Radical (Hetero)Aryl C−H Di‐ and Trifluoromethoxylation
Johnny W. Lee, Sang-Hyun Lim, Daniel N. Maienshein, Peng Liu, Ming‐Yu Ngai
Abstract
Abstract Applications of TEMPO . catalysis for the development of redox‐neutral transformations are rare. Reported here is the first TEMPO . ‐catalyzed, redox‐neutral C−H di‐ and trifluoromethoxylation of (hetero)arenes. The reaction exhibits a broad substrate scope, has high functional‐group tolerance, and can be employed for the late‐stage functionalization of complex druglike molecules. Kinetic measurements, isolation and resubjection of catalytic intermediates, UV/Vis studies, and DFT calculations support the proposed oxidative TEMPO . /TEMPO + redox catalytic cycle. Mechanistic studies also suggest that Li 2 CO 3 plays an important role in preventing catalyst deactivation. These findings will provide new insights into the design and development of novel reactions through redox‐neutral TEMPO . catalysis.