Copper-Catalyzed Trifluoromethylthiolation of Di(hetero)aryl-λ3-iodanes: Mechanistic Insight and Application to Synthesis of (Hetero)Aryl Trifluoromethyl Sulfides

Abstract

The direct and regioselective copper/S-Phos-catalyzed trifluoromethylthiolation of symmetrical and unsymmetrical di(hetero)aryl-λ3-iodanes has been accomplished for the synthesis of various (hetero)aryl trifluoromethyl sulfides employing readily accessible silver trifluoromethylthiolate (AgSCF3) as nucleophilic trifluoromethylthiolating reagent. The developed transformation tolerates various functional groups like nitrile, enolizable ketone, ester, nitro and free carboxylic acid. Interestingly, the formal trifluoromethylthiolation of arenes was also achieved through integration of the synthesis of diaryl-λ3-iodanes from arenes with the trifluoromethylthiolation. Mechanistic investigations did not favor the radical formation and SET pathway. Based on the variable temperature 19F NMR spectroscopy, isolation of the most relevant catalytic intermediate, and stoichiometric studies supported the Cu(I)/Cu(III) catalytic cycle, wherein the oxidative addition of diaryl-λ3-iodanes was assisted by the silver salt.