Visible-Light-Promoted Photocatalytic B-C Coupling via a Boron-Centered Carboranyl Radical: Facile Synthesis of B(3)-Arylated o-Carboranes

A visible-light-mediated insitu generation of a boron-centered carboranyl radical (o-C2B10H11.) has been described. With eosinY as a photoredox catalyst, 3-diazonium-o-carborane tetrafluoroborate [3-N-2-o-C2B10H11][BF4] was converted into the corresponding boron-centered carboranyl radical intermediate, which can undergo efficient electrophilic substitution reaction with a wide range of (hetero)arenes. This general and simple procedure provides a metal-free alternative for the synthesis of 3-(hetero)arylated-o-carboranes.