Sodium Triacetoxyborohydride

Sodium triacetoxyborohydride is a white hygroscopic solid that emits hydrogen gas when hydrolysed in water, which is flammable. It is a milder reducing agent than sodium borohydride or even sodium cyanoborohydride. Even sodium cyanoborohydride is a milder reducing agent than sodium borohydride, and is particularly suitable for the reductive amination of aldehydes and ketones. It can reduce aldehydes but not most ketones.
Sodium triacetoxyborohydride is a mild reagent that exhibits remarkable selectivity as a reducing agent. It reduces aldehydes but not ketones; however, beta-hydroxyketones can be reduced selectively to give 1,3-trans diols.The steric and the electron-withdrawing effects of the three acetoxy groups stabilize the boron-hydrogen bond and are responsible for its mild reducing properties. It can also be used in the reductive alkylation of secondary amines in aldehyde-bisulfite adducts.