Sodium triacetoxyborohydride, also known as sodium triacetoxyhydroborate, commonly abbreviated STAB, is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the formula Na(CH₃COO)₃BH. Like other

borohydride Borohydride refers to the anion , which is also called tetrahydroborate, and its salts. Borohydride or hydroborate is also the term used for compounds containing , where ''n'' is an integer from 0 to 3, for example cyanoborohydride or cyanotrihyd ...

s, it is used as a

reducing agent In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are commonly reducing agents include the Earth me ...

in organic synthesis. This colourless salt is prepared by

protonolysis Protonolysis is the cleavage of a chemical bond by acids. Many examples are found in organometallic chemistry since the reaction requires polar Mδ+-Rδ- bonds, where δ+ and δ- signify partial positive and negative charges associated with the bon ...

of sodium borohydride with acetic acid: :NaBH₄ + 3 HO₂CCH₃ → NaBH(O₂CCH₃)₃ + 3 H₂

Comparison with related reagents

Sodium triacetoxyborohydride is a milder reducing agent than

sodium borohydride Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula Na BH4. This white solid, usually encountered as an aqueous basic solution, is a reducing agent that finds applica ...

or even

sodium cyanoborohydride Sodium cyanoborohydride is the chemical compound with the formula Na B H3 CN. It is a colourless salt, but commercial samples can appear tan. It is widely used in organic synthesis for the reduction of imines. The salt tolerates aqueous conditions ...

. It reduces aldehydes but not most ketones. It is especially suitable for

reductive amination Reductive amination (also known as reductive alkylation) is a form of amination that involves the conversion of a carbonyl group to an amine via an intermediate imine. The carbonyl group is most commonly a ketone or an aldehyde. It is considered ...

s of aldehydes and ketones. However, unlike

, the triacetoxyborohydride hydrolyzes readily, nor is it compatible with methanol. It reacts only slowly with ethanol and isopropanol and can be used with these.
NaBH(OAc)₃ may also be used for reductive alkylation of secondary amines with aldehyde-bisulfite adducts.

Monoacetoxyborohydride

The combination of NaBH₄ 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.{{cite journal, last=Gribble, first=Gordon, W. , title=Sodium borohydride in carboxylic acid media: a phenomenal reduction system, journal=Chemical Society Reviews, date=1998, volume=27, issue=6, pages=395, doi=10.1039/A827395Z, s2cid=96906861 , url=https://semanticscholar.org/paper/a5d0cd1a9b88d7a4120fb72c7bf46ed8547974c1

References

Sodium compounds Borohydrides Reducing agents Acetates

Comparison with related reagents

Monoacetoxyborohydride

See also

References