Sodium triacetoxyborohydride

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Sodium triacetoxyborohydride
Sodium_triacetoxyborohydride
Identifiers
CAS number 56553-60-7 YesY
Properties
Molecular formula C6H10BNaO6
Molar mass 211.96 g/mol
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
Hazards
MSDS External MSDS
EU Index not listed
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Other anions Sodium cyanoborohydride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

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]

NaBH4 + 3 HO2CCH3 → NaBH(O2CCH3)3 + 3 H2

Owing to the steric and electronic effects of the acetoxy groups, sodium triacetoxyborohydride is a milder reducing agent than sodium borohydride or even sodium cyanoborohydride. Furthermore, NaBH(OAc)3 avoids the toxic side-products generated by sodium cyanoborohydride. Sodium triacetoxyborohydride is especially suitable for reductive aminations of aldehydes and ketones.[2][3]

However, unlike sodium cyanoborohydride, the triacetoxyborohydride is water-sensitive and water cannot be used as a solvent with this reagent, neither 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. [4]

References[edit]

  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.  edit
  3. ^ a b 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.  edit
  4. ^ Pandit, C. R.; Mani, N. S. (2009). "Expedient reductive amination of aldehyde bisulfite adducts.". Synthesis (23): 4032–4036.