Sodium triacetoxyborohydride

Sodium triacetoxyborohydride, also known as sodium triacetoxyhydroborate, commonly abbreviated STAB, is a chemical compound with the formula. Like other borohydrides, it is used as a reducing agent in organic synthesis. This colourless salt is prepared by protonolysis of sodium borohydride with acetic acid:

Comparison with related reagents

Sodium triacetoxyborohydride is a milder reducing agent than sodium borohydride or even sodium cyanoborohydride. It reduces aldehydes but not most ketones. It is especially suitable for reductive aminations of aldehydes and ketones.
However, unlike sodium cyanoborohydride, sodium triacetoxyborohydride quickly decomposes upon contact with methanol. It reacts only slowly with ethanol and isopropanol and therefore can be used with these solvents.

[Image:Reductive_amination_of_a_ketone_with_an_amine_using_STAB.svg|400px|center|Reductive amination with STAB]
NaBH₃ may also be used for reductive alkylation of secondary amines with aldehyde-bisulfite adducts.

The combination of with carboxylic acids results in the formation of acyloxyborohydride species other than sodium triacetoxyborohydride. These modified species can perform a variety of reductions not normally associated with borohydride chemistry, such as alcohols to hydrocarbons and nitriles to primary amines.