Direct CÀ H trifluoromethylation of arenes and heteroarenes poses an important synthetic challenge that is highly desirable. High-valent Cu III À CF 3 compounds have often been invoked in copper-mediated trifluoromethylation reactions, but the fundamental reactivity toward arenes is elusive. Herein, direct CÀ H trifluoromethylation of arenes/heteroarenes by a highvalent Cu III À CF 3 compound is disclosed for the first time. The Cu III À CF 3 compound serves CF 3 radical and a Cu II oxidant by homolytic cleavage of a Cu III À CF 3 bond, which engage synergistically in a S E Ar type reaction with arenes. The presence of K 2 S 2 O 8 co-oxidant can significantly improve the reaction yields. This reaction shows good efficiency, broad functional group tolerance, and the potential in late-stage functionalization. The reactivity of high-valent Cu III À CF 3 compounds disclosed in this study represents an important progress in organofluorine and Cu III chemistry.

A convenient method to prepare aryl formates is reported herein that exploits difluorocarbene to serve as a CO surrogate. This reaction is proposed to occur through a sequential O-difluoromethylation of...

A one-pot three-component reaction of two anilines (or one aniline and one alkylamine) and in situ-generated difluorocarbene is developed herein to enable efficient construction of formamidines. Crucial formimidoyl fluoride intermediate RN� CHF is proposed from the reaction of a primary aniline and difluorocarbene. Ensuing nucleophilic iminyl substitution of this intermediate with a second amine allows cross-condensation of the two amines to produce formamidines. When only one type of primary aniline is used as the substrate, the difluoromethylated homo-condensation products can also be produced under a 1:1 molar ratio of aniline/difluorocarbene. Intramolecular variant of this method allows concise synthesis of benzimidazoquinazolines and nitrogen-fused/spirocyclic compounds, showing the potential of this method in organic synthesis. More interesting reactions are anticipated by exploiting the reactivity of difluorocarbene and primary amines to isocyanides or the formimidoyl fluoride intermediates.

Direct CÀ H trifluoromethylation of arenes and heteroarenes poses an important synthetic challenge that is highly desirable. High-valent Cu III À CF 3 compounds have often been invoked in copper-mediated trifluoromethylation reactions, but the fundamental reactivity toward arenes is elusive. Herein, direct CÀ H trifluoromethylation of arenes/heteroarenes by a highvalent Cu III À CF 3 compound is disclosed for the first time. The Cu III À CF 3 compound serves CF 3 radical and a Cu II oxidant by homolytic cleavage of a Cu III À CF 3 bond, which engage synergistically in a S E Ar type reaction with arenes. The presence of K 2 S 2 O 8 co-oxidant can significantly improve the reaction yields. This reaction shows good efficiency, broad functional group tolerance, and the potential in late-stage functionalization. The reactivity of high-valent Cu III À CF 3 compounds disclosed in this study represents an important progress in organofluorine and Cu III chemistry.