Photoinduced Radical Relay Way Toward alpha-CF3 Ketones with Low-Cost Trifluoromethylation Reagents

The utilization of economic and practical trifluoromethyl reagents to introduce trifluoromethyl (CF3) groups into organic molecules is an important research focus due to their role as vital structuralmotifs in the pharmaceutical and agricultural industries. Herein, we disclose a cost-efficient and practical approach of photoinduction of a radical relay process for the synthesis of alpha-CF3 ketones. We showed that trifluoromethylation reagents such as TES-OTf, Tf2O, TMS-OTf, TBS-OTf, H-OTf, and others, could be used successfully as inexpensive CF3 precursors under metal-free and redox-neutral conditions. The potential application of this protocol was highlighted further by late-state modification of drug segments and gram-scale synthesis. Our mechanistic studies revealed that this transformation might involve a radical process, and acetic acid (CH3COOH) not only promoted the formation of enol triflates, but also accelerated the in situ conversion from enol triflates to alpha-CF3 ketones.