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

Names
Other names NaBH(OAc)3; STAB; STABH; Sodium triacetoxyhydroborate
Identifiers
CAS Number	56553-60-7 Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.115.747
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, the triacetoxyborohydride hydrolyzes readily, nor is it compatible with methanol. It reacts only slowly with ethanol and isopropanol and can be used with these.^[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]

References

1. Gordon W. Gribble, Ahmed F. Abdel-Magid, "Sodium Triacetoxyborohydride" Encyclopedia of Reagents for Organic Synthesis, 2007, John Wiley & Sons.doi:10.1002/047084289X.rs112.pub2
2. Abdel-Magid, A. F.; Carson, K. G.; Harris, B. D.; Maryanoff, C. A.; Shah, R. D. (1996). "Reductive Amination of Aldehydes and Ketones with Sodium Triacetoxyborohydride. Studies on Direct and Indirect Reductive Amination Procedures1". The Journal of Organic Chemistry. 61 (11): 3849–3862. doi:10.1021/jo960057x. PMID 11667239.
3. Abdel-Magid, A. F.; Mehrman, S. J. (2006). "A Review on the Use of Sodium Triacetoxyborohydride in the Reductive Amination of Ketones and Aldehydes". Organic Process Research & Development. 10 (5): 971. doi:10.1021/op0601013.
4. Magano, Javier; Kiser, E. Jason; Shine, Russell J.; Chen, Michael H. (2013). "Oxindole Synthesis via Palladium-catalyzed C-H Functionalization". Organic Syntheses. 90: 74. doi:10.15227/orgsyn.090.0074.
5. Pandit, C. R.; Mani, N. S. (2009). "Expedient reductive amination of aldehyde bisulfite adducts". Synthesis (23): 4032–4036.
6. Gribble, Gordon, W. (1998). "Sodium borohydride in carboxylic acid media: a phenomenal reduction system". Chemical Society Reviews. 27 (6): 395. doi:10.1039/A827395Z. S2CID 96906861.{{cite journal}}: CS1 maint: multiple names: authors list (link)
7. Houri, Ahmad F.; Hoveyda, Amir H. (2001). "Tetramethylammonium Triacetoxyborohydride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rt059. ISBN 0-471-93623-5.