Decarboxylative and Denitrative Trifluoromethylation for the Synthesis of C-vinyl-CF3 Compounds with Togni (II) Reagent

摘要

A highly efficient dimethylformamide (DMF)-promoted decarboxylative trifluoromethylation of alpha,beta-unsaturated carboxylic acids with Togni (II) reagent under metal-free conditions has been developed. The reactions showed good yields, high stereoselectivities and excellent functional group tolerance. Mechanistic studies confirmed that free-radical processes were involved in this system since the CF3 radical had been clearly trapped by scavengers. This method has been extended to the denitrative trifluoromethylation of beta-nitrostyrenes in the presence of an iron(III) catalyst.