Formal [3+2] Reaction of α,α-Diaryl Allylic Alcohols with sec-Alcohols: Proceeding with Sequential Radical Addition/Migration toward 2,3-Dihydrofurans Bearing Quaternary Carbon Centers

An unprecedented TBHP-promoted formal [3 + 2] annulation of sec-alcohols with alpha,alpha-diaryl allylic alcohols has been developed, leading to 2,3-dihydrofurans in moderate to excellent yields with good functional group tolerance. This procedure involves sequential radical addition, 1,2-aryl migration, and a dehydration process, where the migration of aryl with lower electron density is favored. Notably, cyclic reactions with sec-alcohols also ran smoothly, providing a novel method to access oxaspiro compounds.