Photoexcited acetophenone can catalyze the fluorination of unactivatedC(sp(3))-H groups. While acetophenone, a colorless oil, only has a trace amount of absorption in the visiblelight region, its photoexcitation can be achieved by irradiation with light generated by a household compact fluorescent lamp (CFL). This operational simple method provides improved substrate scope for the direct incorporation
Careful examination of nucleophilicity, basicity, and leaving group ability led us to discover the nucleophilic fluorination of triflates by weakly basic tetrabutylammonium bifluoride, which provides excellent yields with minimal formation of elimination-derived side products. Primary hydroxyl groups as well as secondary hydroxyl groups in acyclic chains or in five-membered rings are excellent substrates, whereas benzylic and aldol-type secondary hydroxyl groups give poor yields as a result of the instability of their triflates.