Reduction of sulfoxides with boranes catalyzed by MoO2Cl2

The first example of an organic reduction with boranes catalyzed by a high valent oxo-complex is reported. The systems catecholborane/MoO2Cl2(H2O)2 (5 mol %) and BH3·THF/MoO2Cl2 (5 mol %) proved to be very efficient for the reduction of sulfoxides to the corresponding sulfides in excellent yields.

The dioxomolybdenum dichloride, MoO2Cl2, proved to be an excellent catalyst for the reduction of sulfoxides with boranes.