Chapter 5 - Bismuth Compounds in Organic Transformations

Abstract

This chapter deals with a variety of organic transformations based on the use of metallic bismuth, inorganic bismuth salts, bismuth-added inorganic oxides and salts, and trivalent/pentavalent organobismuth compounds. The reactions are classified according to their reaction types, and are presented in the order of oxidation, reduction, carbon-carbon bond forming reactions, and carbon-heteroatom bond forming reactions. The first report of organic transformation using bismuth compounds was made by Challenger in 1934 and involved the oxidation of alcohols to the corresponding carbonyl compounds with bismuth(V) compounds. About two decades later, sodium bismuthate and bismuth oxide were reported by Rigby to be effective as a mild oxidant for alcohols. During the following two decades, however, bismuth compounds were mainly studied as the promoter for organic reactions. In the 1960s, bismuth molybdate phases were used for the effective transformation of propylene to acrolein and acrylonitrile, where bismuth was one of the key components of the solid-phase catalysts for propane and propylene oxidations. Intensive studies have been made by Barton's and Dodonov's groups on pentavalent organobismuth compounds as oxidant and/or arylating agent from the late 1970s to the 1980s. The chemistry of bismuthonium salts and ylides started in the late 1980s. Recently, many bismuth compounds have been gaining increasing attention as catalysts as well as reaction mediators. Typically, bismuth mandelate and triflate are effective as catalysts for molecular oxygenation and Friedel-Crafts acylation, respectively. Most of the bismuth compounds commercially available are not expensive, easy to handle, and non-toxic.