Iron-Catalyzed Hydroboration of Vinylcyclopropanes.

An iron-catalyzed hydroboration of vinylcyclopropane with HBpin is first reported for the preparation of valuable homoallylic organoboronic esters. The iron catalysts enable efficient and regioselective C-C cleavage of vinylcyclopropanes, stereoselectively delivering E-alkenes with good stereospecific selectivity at an allylic position. This protocol exhibits mild conditions with good functional group tolerability. The chiral homoallylic organoboronic esters could be further converted into chiral polysubstituted tetrahydrofuran and tetrahydropyran.