NaBArF‑Mediated Electrophilic Trifluoromethylation of Nonactivated Silyl Enol Ethers.

In this work, a mild NaBArF-mediated electrophilic trifluoromethylation of nonactivated silyl enol ethers is reported, using an Umemoto-type chloride salt thanks to a reactivity-modulation through its counter-anion. Hence, the key to success is the catalytic generation of a highly reactive Umemoto trifluoromethylating agent with the non-coordinative BArF 24 anion upon in situ anion exchange initiated by catalytic amounts of the commercially available and simple NaBArF 24 salt. This alternative method enables a selective reaction towards α-trifluoromethylated ketones under mild reaction conditions and avoids the use of stoichiometric Sn reagents, offering a practical strategy for embracing further highly demanding substrates in trifluoromethylation reactions.