Synthesis of α-Trifluoromethylated Ketones from α,β-Unsaturated Ketones via Catecholboron Enolates

Herein, we report a protocol for the synthesis of alpha-trifluoromethylated ketones through trifluoromethylation of the corresponding catecholboron enolates of alpha,beta-unsaturated ketones. The reaction of the 1,4-hydroborated product of enones with the Togni II reagent affords the alpha-trifluoromethylated ketones without any catalyst or additive. Moreover, the protocol has been employed on a series of alpha,beta-unsaturated ketones, including chalcones, substrate-bearing heterocycles, and bioactive molecules. Mechanistic studies suggest the involvement of a trifluoromethyl radical during the reaction.