Development of Electrophilic Trifluoromethylating Reagents

Abstract Electrophilic trifluoromethylating reagents developed so far are classified into three categories, and their syntheses and reactivities are described chronologically. The reagents include S -(trifluoromethyl)diarylsulfonium salts, S -(trifluoromethyl)dibenzothiophenium salts (Umemoto’s reagents), Se -(trifluoromethyl)dibenzoselenophenium salts, Te -(trifluoromethyl)dibenzotellurophenium salts, O -(trifluoromethyl)dibenzofuranium salts, 1-(trifluoromethyl)-1,2-benziodoxol-3(1H)-one (Togni’s reagent), 1-(trifluoromethyl)-1,3-dihydro-3,3-dimethyl-1,2-benziodoxole (Togni’s reagent), S -trifluoromethyl sulfoximinium salts, S -(trifluoromethyl)benzothiophenium salts, and S -trifluoromethyl sulfonium ylides.