Synlett 2010(11): 1729-1730  
DOI: 10.1055/s-0029-1219952
SPOTLIGHT
© Georg Thieme Verlag Stuttgart ˙ New York

Sodium Triacetoxyborohydride

Lakhinath Saikia*
Department of Chemical Sciences, Tezpur University, Assam 784028, India
e-Mail: lakhi@tezu.ernet.in;
Further Information

Publication History

Publication Date:
11 June 2010 (online)

Introduction

Sodium triacetoxyborohydride [Na(OAc)3BH, abbreviated as STAB-H] is a versatile reagent in organic synthesis. In addition to its superior ability in effecting reductive amination of aldehydes and ketones, it can reduce N-heterocycles (indoles, quinolines, and isoquinolines), imines, enamines, oximes, amides, aryl ketones, acetals, and other substrates. [¹]

STAB-H is a milder and more selective reducing agent than NaBH4. The mild nature of STAB-H may be attributed both to the bulky nature of the reagent and to the inductive electron-withdrawing ability of the three acetoxy groups which stabilize the boron-hydrogen bond. [²] It has more advantages over Na(CN)BH3 also due to the lack of toxicity.

The preparation of triacetoxyborohydride was first performed by Wartik and Pearson through the reaction of NaBH4 and CO2 (Scheme  [¹] ). [³] Furthermore, it can be also generated in situ from NaBH4 and acetic acid. Aldehydes, but not ketones, are smoothly reduced to alcohols with STAB-H, prepared from sodium borohydride and acetic acid in benzene [4] or in N,N-dimethylacetamide. [5]

Scheme 1

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