Aromatic C–H Thioalkylphosphinylation of [2.2]Paracyclophanes via Sulfonium Salts

Base-enabled aromatic C-H functionalization of [2.2]paracyclophanes was achieved by thioalkylphosphinylation via sulfonium salts. Cross-coupling between [2.2]paracyclophane tetrahydro-1<i>H</i>-thiophen-1-ium trifluoromethanesulfonates and secondary phosphine oxides afforded thioalkylphosphinylated [2.2]paracyclophane derivatives through selective C(sp³)-S bond cleavage of the arylsulfonium salts under mild conditions. The protocol features broad substrate scopes, good functional group tolerance from readily available reagents, and decent efficiency in up to 96% yields. The practicability of this method was demonstrated by scale-up preparation of the target products and their transformations to potential P,S-ligands for Suzuki and Sonogashira cross-coupling reactions.