Selective Reduction of Ketones Using Water as a Hydrogen Source under high Hydrostatic Pressure
A selective reduction of a broad variety of ketones is described. The method is based on the combination of a Ni–Al alloy and high hydrostatic pressure (HHP, 2.8 kbar) in an aqueous medium. The reaction of the Ni–Al alloy with water provides in situ hydrogen generation and the high pressure ensures that the H2 formed remains in the solution, thus the CvO reduction readily occurs. The application of the HHP resulted in selective formation of the desired products and the common problem of non-selective overhydrogenation could be avoided. In most cases the reductions resulted in high yields and excellent selectivities without the use of any base.