Photocatalytic borylcyclopropanation of α-boryl styrenes

A diastereoselective borylcyclopropanation of a-MIDA-boryl styrenes with 1,1-diiodoborylmethane is developed using 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) as a catalyst under visiblelight irradiation. The scope of this photocatalytic method is explored, and the utility of the resulting doubly borylated cyclopropanes is demonstrated by the selective transformation of one of the two boryl groups.