Sulfur Transfer Reagents in Heterocyclic Synthesis

Publisher Summary Many sulfur-containing heterocyclic compounds can be constructed by a reaction between an organic moiety and a simple, often inorganic, sulfur compound. This chapter discusses the sulfur compounds and the typical heterocycle-forming reactions they undergo. In such reactions the sulfur atom, or a small group of contiguous atoms of which sulfur is one, is transferred to the organic substrate. The heating together of sulfur and an organic compound is the simplest possible heterocycle-forming reaction. Sulfur halides and related compounds of divalent sulfur are discussed. The reversible reaction between butadiene and sulfur dioxide, which yields sulfolene, has been known for a long time. Such cycloaddition reactions of sulfur dioxide, and of other sulfur oxides, are reviewed. Thionyl chloride (SOCl) is the most versatile of all sulfur transfer reagents in heterocyclic synthesis.