Reduction of Aldehydes and Ketones to Alcohols
Reduction of Aldehydes and Ketones to Alcohols: Hydride Exchange at Sodium Borohydride
During the reduction of aldehydes and ketones, the transfer of all four hydride anions of sodium borohydride occurs sequentially. One mol of ketone is reduced with 1/4 mol of sodium borohydride. In addition to the borohydride anion, three different reducing agents are involved in the reduction. This makes for a difficult interpretation of reaction rate and stereoselectivity.
The reduction with sodium borohydride is carried out in either aqueous or alcohol solution resulting in the hydrolysis of the initially formed alkoxyborate by the solvent to the corresponding alcohols.