Sodium triacetoxyborohydride

Sodium triacetoxyborohydride, also known as sodium triacetoxyhydroborate, commonly abbreviated STAB, is a chemical compound with the formula Na[(CH₃COO)₃BH]. 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:^[1]

Na[BH₄] + 3 CH₃COOH → Na[(CH₃COO)₃BH] + 3 H₂

Sodium triacetoxyborohydride

Sodium_triacetoxyborohydride
Names
Other names NaBH(OAc)3; STAB; STABH; Sodium triacetoxyhydroborate
Identifiers
CAS Number	56553-60-7 Y
3D model (JSmol)	Interactive image
ChemSpider	2007055
ECHA InfoCard	100.115.747
EC Number	611-401-0
PubChem CID	23676153
UNII	4VU0JE4YSK Y
CompTox Dashboard (EPA)	DTXSID8074368
InChI InChI=1S/C6H9BO6.Na/c1-4(8)11-7(12-5(2)9)13-6(3)10;/h1-3H3;/q-1;+1 Key: AGGHKNBCHLWKHY-UHFFFAOYSA-N
SMILES [BH-](OC(=O)C)(OC(=O)C)OC(=O)C.[Na+]
Properties
Chemical formula	Na[(CH3COO)3BH]
Molar mass	211.94 g·mol−1
Appearance	White powder
Density	1.20 g/cm3
Melting point	116 to 120 °C (241 to 248 °F; 389 to 393 K) decomposes
Solubility in water	decomposition
Structure
Coordination geometry	4 at boron atom
Molecular shape	Tetrahedral at boron atom
Hazards
NFPA 704 (fire diamond)	3 4 2
Safety data sheet (SDS)	External MSDS
Related compounds
Other anions	Sodium cyanoborohydride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

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.^[2][3][4]

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.^[3]

Reductive amination with STAB

NaBH(OAc)₃ may also be used for reductive alkylation of secondary amines with aldehyde-bisulfite adducts. ^[5]

Monoacetoxyborohydride

The combination of Na[BH₄] 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.^[6]

See also

• Sodium cyanoborohydride - a slightly stronger reductant, but amenable to protic solvents
• Sodium borohydride - a stronger, cheaper reductant
• Tetramethylammonium triacetoxyborohydride^[7]