Oxy-trifluoromethylation of alkenes and its application to the synthesis of β-trifluoromethylstyrene derivatives

Oxy-trifluoromethylation of di-substituted styrenes and dienes was achieved by using Cu/Togni's reagent system. Not only gem-di-substituted styrenes, but also a β-methylstyrene derivative were transformed to the corresponding oxy-trifluoromethylation products. 1,4-Addition products were obtained selectively in the reaction of mono-substituted dienes. These reactions provide a new approach for the synthesis of β-trifluoromethyl styrene derivatives.