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sodium triacetoxyborohydride

{{chembox

| verifiedrevid = 415899026

| Name = Sodium triacetoxyborohydride

| ImageFile = Sodium_triacetoxyborohydride.svg

| ImageSize = 150px

| ImageName = Sodium_triacetoxyborohydride

| OtherNames = NaBH(OAc)3; STAB; STABH; Sodium triacetoxyhydroborate

| Section1 = {{Chembox Identifiers

| CASNo = 56553-60-7

| CASNo_Ref = {{cascite|correct|CAS}}

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 4VU0JE4YSK

| EINECS =

| PubChem = 23676153

| InChI = 1S/C6H9BO6.Na/c1-4(8)11-7(12-5(2)9)13-6(3)10;/h1-3H3;/q-1;+1

| InChIKey = AGGHKNBCHLWKHY-UHFFFAOYSA-N

| SMILES = [BH-](OC(=O)C)(OC(=O)C)OC(=O)C.[Na+]

}}

| Section2 = {{Chembox Properties

| Formula = {{chem2|Na[(CH3COO)3BH]}}

| C=6 | H=10 | B=1 | Na=1 | O=6

| Appearance = White powder

| Density = 1.20 g/cm3

| Solubility = decomposition

| MeltingPtC = 116 to 120

| MeltingPt_notes = decomposes

}}

| Section3 = {{Chembox Structure

| Coordination = 4 at boron atom

| MolShape = Tetrahedral at boron atom

}}

| Section7 = {{Chembox Hazards

| ExternalSDS = [http://www.sciencelab.com/msds.php?msdsId=9925052 External MSDS]

| NFPA-H = 3

| NFPA-R = 2

| NFPA-F = 4

| NFPA-S =

}}

| Section8 = {{Chembox Related

| OtherAnions = Sodium cyanoborohydride

| OtherCations =

| OtherCompounds =

}}

}}

Sodium triacetoxyborohydride, also known as sodium triacetoxyhydroborate, commonly abbreviated STAB, is a chemical compound with the formula {{chem2|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: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}}

:{{chem2|Na[BH4] + 3 CH3COOH → Na[(CH3COO)3BH] + 3 H2}}

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.{{cite journal | last1 = Abdel-Magid | first1 = A. F. | last2 = Carson | first2 = K. G. | last3 = Harris | first3 = B. D. | last4 = Maryanoff | first4 = C. A. | last5 = Shah | first5 = R. D. | title = Reductive Amination of Aldehydes and Ketones with Sodium Triacetoxyborohydride. Studies on Direct and Indirect Reductive Amination Procedures1 | doi = 10.1021/jo960057x | journal = The Journal of Organic Chemistry | volume = 61 | issue = 11 | pages = 3849–3862 | year = 1996 | pmid = 11667239}}{{cite journal | last1 = Abdel-Magid | first1 = A. F. | last2 = Mehrman | first2 = S. J. | doi = 10.1021/op0601013 | title = A Review on the Use of Sodium Triacetoxyborohydride in the Reductive Amination of Ketones and Aldehydes | journal = Organic Process Research & Development | volume = 10 | issue = 5 | pages = 971 | year = 2006 }}{{cite journal |doi=10.15227/orgsyn.090.0074|title=Oxindole Synthesis via Palladium-catalyzed C-H Functionalization|journal=Organic Syntheses|year=2013|volume=90|page=74|first1=Javier|last1=Magano|first2=E. Jason|last2= Kiser|first3=Russell J.|last3=Shine|first4=Michael H.|last4=Chen|doi-access=free}}

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.


Image:Reductive_amination_of_a_ketone_with_an_amine_using_STAB.svg

NaBH(OAc)3 may also be used for reductive alkylation of secondary amines with aldehyde-bisulfite adducts. {{cite journal | journal = Synthesis | title = Expedient reductive amination of aldehyde bisulfite adducts. | year = 2009 | last1 = Pandit | first1 = C. R. | last2 = Mani | first2 = N. S. | issue = 23 | pages = 4032–4036}}

Monoacetoxyborohydride

The combination of {{chem2|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.{{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 }}

See also

  • Sodium cyanoborohydride - a slightly stronger reductant, but amenable to protic solvents
  • Sodium borohydride - a stronger, cheaper reductant
  • Tetramethylammonium triacetoxyborohydride{{cite book |doi=10.1002/047084289X.rt059 |chapter=Tetramethylammonium Triacetoxyborohydride |title=Encyclopedia of Reagents for Organic Synthesis |date=2001 |last1=Houri |first1=Ahmad F. |last2=Hoveyda |first2=Amir H. |isbn=0-471-93623-5 }}

References

Category:Sodium compounds

Category:Borohydrides

Category:Reducing agents

Category:Acetates