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Synlett 2005(4): 711-712  
DOI: 10.1055/s-2005-863726
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© Georg Thieme Verlag Stuttgart · New York

Indium Tribromide: A Water-Tolerant Green Lewis Acid

Zhan-Hui Zhang*
College of Chemistry, Hebei Normal University, Shijiazhuang 050091, P. R. China
e-Mail: zhanhui@126.com;
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Publication History

Publication Date:
22 February 2005 (online)

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Introduction

Recently, indium tribromide has received increasing attention as a novel type of water-tolerant green Lewis acid catalyst for organic synthesis with highly chemo-, regio- and stereoselective results. [1] Compared to conventional Lewis acids, it has advantages of water stability, recyclability, operational simplicity, strong tolerance to oxygen- and nitrogen-containing reaction substrates and functional groups, and it can often be used in just catalytic amounts. This catalyst promotes various transformations including alknylation of aldehydes and N,O-acetals, [2] Michael addition, [3] synthesis of 1,3-dioxane derivatives, [4] conversion of oxiranes to thiiranes, [5] sulfonation of indoles, [6] alkynylat­ion of acid chorides [7] and synthesis of 2-halo-1,3-dienes. [8]

Indium tribromide is conveniently prepared by heating metallic indium in a current of nitrogen and bromine, [9] and is now also commercially available.