Cis-Difluoromethyl Hetarylative Dearomatization by Radical Docking-Migration Cascade

Abstract

Despite the significant advances in dearomatization reactions, the challenge of achieving uncyclized dearomatization to produce thermodynamically unstable 1,2-cis-products remains unresolved. Here we present a novel approach for uncyclized cis-selective dearomatization reaction via a radical docking-migration cascade. The reaction proceeds under mild photochemical conditions, simultaneously incorporating a CF₂H and a hetaryl group into indoline backbones. A wide range of indoles with diverse functional groups are compatible with the reaction. Furthermore, this method is also suitable for the dearomatization of benzothiophenes, furans, thiophenes and a few polycyclic aromatic hydrocarbons. This protocol features excellent selectivities, broad product diversity, and the unnecessity of photosensitizers. DFT calculations rationalize the observed regioselectivities for various heteroarenes and cis-stereoselectivities.