Ion-Pair-Catalyzed Sodium Borohydride Reduction in Aprotic Organic Solvents

Sodium borohydride reduction in aprotic solvents has always been an unsolved problem. In this work a ion-pair-catalyzed sodium borohydride reduction in aprotic solvents was kinetically and mechanistically studied. Finally sodium borohydride reduction could be carried out in common aprotic solvents efficiently under mild conditions. A large quantity of water or methanol as the solvent or co-solvent has been avoided. The generation of stoichiometric or excess organic ammonium waste has also been avoided. The normal acidic work-up is not necessary and the catalyst was recycled.