Photocatalytic Transfer of Trifluoromethylcarbenes for X–H Insertion, Oxetane Skeleton Editing, and Alkene Cyclopropanation

Although trifluoromethylcarbene chemistry has garnered significant attention for its capacity to concurrently install a CF₃ group and forge two new bonds─thus enabling the rapid assembly of molecular complexity─prevailing methods depend almost exclusively on transition-metal catalysis, which proceeds via metal-carbene intermediates. To overcome this limitation, we report a mild, general, and transition-metal-free photocatalytic strategy that employs bench-stable sulfonyl hydrazones as trifluoromethylcarbene precursors. Using a commercially available organic photocatalyst under visible light, this method can generate free trifluoromethylcarbene, facilitating its transfer in a range of transformations, including X-H (X = O, N, S, Si) insertions, cyclopropanation of alkenes, and the unprecedented skeletal editing of oxetanes via trifluoromethylcarbene insertion.