Sulfines

Sulfines are a class of organosulfur compounds with the general formula R2C=S=O. They are characterized by a sulfur atom double-bonded to a carbon atom and also bonded to two oxygen atoms, which are often depicted as a double bond or two single bonds to an oxygen atom in resonance structures, but are typically represented as a cumulative double bond to sulfur. Sulfines can be viewed as analogs of sulfenes (R2C=SO2) where one of the doubly bonded oxygen atoms is replaced by a lone pair. The sulfur atom in a sulfine is in a high oxidation state.

The synthesis of sulfines can be achieved through various methods, including the oxidation of sulfenes or the reaction of sulfinyl chlorides with ylides. They are generally reactive species and can undergo various transformations, such as cycloaddition reactions and nucleophilic additions. Due to their reactivity, sulfines are often generated in situ and used immediately in subsequent reactions. Their chemistry is of interest in organic synthesis for the construction of complex sulfur-containing molecules. The presence of the exocyclic double bond to sulfur makes them electrophilic at the sulfur atom and also allows for nucleophilic attack at the carbon atom under certain conditions. The electronic properties of the substituents on the carbon atom can significantly influence the reactivity and stability of the sulfine.