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
3D model (JSmol)
ECHA InfoCard 100.115.747
UNII
  • 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
  • [B-H](OC(=O)C)(OC(=O)C)OC(=O)C.[Na+]
Properties
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
decomposition
Structure
4 at boron atom
Tetrahedral at boron atom
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored 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).
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Infobox references

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
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


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)
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