Desulfination as an Emerging Strategy in Palladium-Catalyzed C-C Coupling Reactions

As carbon-carbon bonds are an essential bond type in Nature, reactions that form C-C bonds are of great interest in organic chemistry. Among the most popular C-C bond formation methods with aromatic systems are palladium-catalyzed coupling reactions, such as the Heck, Suzuki, Negishi and Stille reactions. Even though these methods are efficient, they produce stoichiometric amounts of high molecular weight byproducts, placing them in conflict with the increasingly important ideas of sustainable reactions and green chemistry. In contrast, palladium-catalyzed desulfinative coupling reactions produce minimal waste; in general, only hydrogen halides or alkali halides are formed as byproducts in addition to SO2 gas, which can potentially be recycled. This microreview provides a brief historic overview on palladium-catalyzed coupling reactions with organosulfur compounds, with the main focus on the use of sulfinate salts as nucleophilic or electrophilic reaction partners. Various methods to access the sulfinate salts, and the coupling reactions of sulfonyl precursors that proceed through sulfinic acid/salt intermediates generated in situ are also discussed.