Sulfene
Sulfenes are a class of highly reactive organosulfur compounds characterized by the general formula R1R2C=SO2, where R1 and R2 are organic substituents. They are the sulfur analogues of ketenes. Sulfenes are unstable and are typically generated in situ and trapped by reaction with nucleophiles or dienes.
Their instability stems from the weak S=O pi-bonds and the potential for facile rearrangements. They are often synthesized by the dehydrohalogenation of sulfonyl chlorides in the presence of a base.
Sulfenes participate in a variety of reactions, most notably cycloadditions, particularly Diels-Alder reactions, forming cyclic sulfones. They also react readily with alcohols, amines, and other nucleophiles to form sulfonate esters, sulfonamides, and other sulfonated products. Due to their reactivity, sulfenes are valuable intermediates in organic synthesis. The nature of the substituents R1 and R2 significantly influences the stability and reactivity of the sulfene.