Recent Advances and Perspectives in the Chemistry of Sulfenic Acids

This review provides a comprehensive survey of the literature on sulfenic acid chemistry from 1990 through June 2006, focusing the attention on salient aspects of their structures and involvement in organic processes. Even if the majority of known sulfenic acids cannot be isolated, some stable ones have been obtained, and their study helped dramatically the comprehension of chemical and physical properties of all sulfenic acids and indirectly of the role that Cys-SOHs play in protein biochemistry. Many papers have been published in the last fifteen years about the sulfenic acid intermediacy in organic chemistry. Once generated, they can be involved in intra- and intermolecular additions to unsaturated molecules. Few examples of sulfenic acid addition to double bonds have been recently described and most of them are intramolecular processes, whereas the addition of enantiopure sulfenic acids onto carbon-carbon triple bonds has been widely exploited in the synthesis of vinyl sulfoxides to be used in many stereoselective transformations. The thermic β- elimination from sulfinyl precursors is a way to generate sulfenic acids but it has been also used for removing the sulfinyl moiety from organic molecules and forming double bonds with controlled stereochemistry. Some significant applications of extrusion processes are also described in the present review.