Reactivity of triphosphinoboranes towards HB·SMe: access to derivatives of boraphosphacycloalkanes with diverse substituents.

Triphosphinoboranes activated the B-H bond in the BH molecule without any catalysts at room temperature. Hydroboration reactions led to boraphosphacyloalkanes with diverse structures. The outcomes of reactions depend on the size of the phosphanyl substituent on the boron atom of the parent triphosphinoborane, where derivatives of boraphosphacyclobutane and boraphosphacyclohexane were obtained. Furthermore, the precursor of triphosphinoboranes, namely bromodiphosphinoborane, also exhibited high reactivity towards HB·SMe, yielding bromo-substituted boraphosphacyclobutane. The obtained products were characterized by heteronuclear NMR spectroscopy, single crystal X-ray diffraction, and elemental analysis.