4.23 Stetter Reaction

Abstract

The 1,4-dicarbonyl motif is present in a large variety of natural products and active pharmaceutical ingredients. Compounds featuring this motif are also useful synthetic intermediates, such as in the synthesis of heterocycles. Consequently, a number of reactions have been developed to access this important structural pattern. Among them, the Stetter reaction stands as a powerful approach in which a new carbon–carbon bond is formed through the catalysis of a variety of azolium salts. The availability of a wide range of azolium salts, including chiral ones, makes the Stetter reaction a useful tool in enantioselective synthesis. This chapter provides a review of intra- and intermolecular Stetter reactions with an emphasis on recent enantioselective variants and on their application to total synthesis. Related processes utilizing aldehyde surrogates or unactivated alkenes are also covered in this chapter.