Rhodium-Catalyzed Divergent Arylation of Alkenylsulfonium Salts with Arylboroxines.

A ligand-controlled rhodium-catalyzed regiodivergent arylation of alkenylthianthrenium salts with arylboroxines which allows the synthesis of terminal and internal alkene products in a switchable manner is reported. The use of a diene ligand guides the reaction toward cine-arylation affording terminal alkenes, while the use of a phosphine ligand switches the reaction to ipso-arylation exclusively giving internal alkenes. Deuterium labelling studies and DFT computations were carried out to investigate the mechanism.