Efficient Water Reduction with sp3 -sp3 Diboron(4) Compounds: Application to Hydrogenations, H-D Exchange Reactions, and Carbonyl Reductions.

A series of crystalline sp3 -sp3 diboron(4) compounds were synthesized and shown to promote the facile reduction of water with dihydrogen formation. The application of these diborons as simple and effective dihydrogen and dideuterium sources was demonstrated by conducting a series of selective reductions of alkynes and alkenes, and hydrogen-deuterium exchange reactions using two-chamber reactors. Finally, as the water reduction reaction generates an intermediate borohydride species, a range of aldehydes and ketones were reduced by using water as the hydride source.