Abstract
The reaction of p‐tolyl(phenylthio)sulfine 1 [TolC(SPh)SO, Tol=p‐MeC~6~H~4~] with α‐oxo‐carbanions is described. With 2‐lithiocyclohexanone, sulfine 1 furnishes alkene disulfide 2. Similarly, the carbanion of 3,4‐dihydro‐1‐naphthalenone (α‐tetralone) gives disulfide 5. This introduction of a C(Tol)SSPh group into the α‐position of the ketone is explained by assuming an initial carbophilic displacement of the SPh substituent in 1 by the carbanion. Deprotonation of the so‐obtained β‐oxosulfine 3 gives a vinylsulfenate which in a subsequent reaction with thiophenol produces disulfides 2 and 5, respectively. The suggested intermediate vinylsulfenates could be trapped by a reaction with electrophilic reagents. With methyl iodide or benzyl bromide γ‐oxo‐α,β‐unsaturated sulfoxides 6–9 were obtained [introduction of a C(Tol)S(O)R group (R Me, CH~2~Ph) in the position α to the carbonyl function of the ketone]. With ethyl bromoacetate or phenacyl bromide the vinylsulfenate obtained from 1 and α‐tetralone does not lead to unsaturated sulfoxides, but to 4,5‐dihydro‐naphtho[1,2‐c]thiophene S‐oxides 15 and 16 instead. These thiophene S‐oxides are thought to arise from an intramolecular condensation of the primary products, i.e. γ‐oxo‐α,β‐unsaturated sulfoxides 21.