Sodium triacetoxyborohydride
[CAS# 56553-60-7]

Identification

• Classification: Organic raw materials >> Organometallic salt
• Name: Sodium triacetoxyborohydride
• Synonyms: STAB
• Molecular Formula: C₆H₁₀BNaO₆
• Molecular Weight: 211.94
• CAS Registry Number: 56553-60-7
• EC Number: 435-580-8
• SMILES: CC(=O)O[BH-](OC(C)=O)OC(C)=O.[Na+]

Properties

• Density: 1.43 g/mL (Expl.)
• Melting point: 116-120 °C (decomp.) (Expl.)
• Water solubility: reacts

Safety Data

• Hazard Symbols: GHS02;GHS05;GHS07 Danger
• Risk Statements: H228-H261-H315-H318-H335
• Safety Statements: P223-P210-P231+P232-P305+P351+P338-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Serious eye damage	Eye Dam.	1	H318
Substances or mixtures which in contact with water emit flammable gases	Water-react.	1	H260
Reproductive toxicity	Repr.	1B	H360
Skin irritation	Skin Irrit.	2	H315
Flammable solids	Flam. Sol.	1	H228
Self-reactive substances or mixtures	Self-react.	E	H242
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - single exposure	STOT SE	3	H335
Flammable solids	Flam. Sol.	2	H228
Reproductive toxicity	Repr.	1B	H360FD
Substances or mixtures which in contact with water emit flammable gases	Water-react.	3	H261
Specific target organ toxicity - single exposure	STOT SE	3	H336

• Transport Information: UN 1409

Discovery and Applications

Sodium triacetoxyborohydride is a chemical compound with the formula NaBH(OCOCH3)3. It is a white to off-white crystalline solid, and it is commonly used as a mild reducing agent in organic synthesis. The compound consists of a boron atom bonded to three acetoxy groups (–OCOCH3) and a hydride ion (H–), which allows it to reduce a variety of functional groups under mild conditions.

The discovery of sodium triacetoxyborohydride can be traced back to the development of borohydride chemistry. Sodium triacetoxyborohydride was first synthesized and characterized in the 1960s as part of ongoing efforts to create selective and mild reducing agents for organic synthesis. The compound was developed as an alternative to other more reactive reducing agents, such as sodium borohydride (NaBH4) and lithium aluminum hydride (LiAlH4), which are often too strong for some sensitive reactions.

Sodium triacetoxyborohydride is widely used in organic chemistry for the selective reduction of carbonyl compounds, including aldehydes and ketones. Its advantage over sodium borohydride lies in its milder reactivity, which makes it suitable for reducing more sensitive substrates, such as esters, lactones, and imines. In many cases, sodium triacetoxyborohydride offers high selectivity and low reactivity toward other functional groups, making it an ideal choice for complex reductions in the synthesis of pharmaceuticals and fine chemicals.

One of the most common applications of sodium triacetoxyborohydride is in the reduction of α,β-unsaturated carbonyl compounds, which are often resistant to reduction by other agents. The compound is also employed in the selective reduction of esters to aldehydes or alcohols without over-reducing the substrate. This selective reactivity is particularly valuable in the synthesis of complex molecules where controlling the reduction process is critical.

Beyond organic synthesis, sodium triacetoxyborohydride is used in various synthetic applications, including the reduction of nitro groups to amines and the reduction of other electron-deficient functional groups. Its role as a reducing agent extends to polymer chemistry as well, where it is used in polymer modification processes.

In conclusion, sodium triacetoxyborohydride is a well-established reducing agent in organic synthesis, prized for its mild and selective reduction properties. It plays a crucial role in the synthesis of pharmaceuticals, agrochemicals, and other fine chemicals, allowing for precise control in the reduction of a wide range of functional groups.

References

2002. Use of sodium triacetoxyborohydride in the synthesis of nitroxide biradicals. J. Chem. Soc., Perkin Trans. 1, (24).
DOI: 10.1039/b208263b

2013. Synthesis and Crystal Structures of N,N'-Disubstituted Piperazines. Journal of Chemical Crystallography, 43(8).
DOI: 10.1007/s10870-012-0346-1

2002. Reactions of Sodium Borohydride in Acetic Acid: Reductive Amination of Carbonyl Compounds. Pharmaceutical Chemistry Journal, 36(1).
DOI: 10.1023/A:1005221508362