Introduction of Sulfur Atoms into Trifluoromethylated Alkenyl Sulfones and Chlorides Using a Reactive Sulfur-Graphite Electrode

The introduction of sulfur atoms into trifluoromethylated alkenyl sulfones and chlorides were studied using a reactive sulfur-graphite electrode in N,N-dimethylformamide. A substrate, 2-(4-biphenylyl)-4,4,4-trifluoro-3-phenylsulfonyl-2-butenenitrile (1a) afforded a coupling compound bridged with a nitrogen atom of isothiazole and 1,2-dithiolane skeleton (2). 1-(4-Biphenylyl)-3,3,3-trifluoro-2-phenylsulfonylpropene (1b) without a cyano group gave a complex oligomeric compound (3) without the elimination of the phenylsulfonyl group. 2-(4-Biphenylyl)-3-chloro-4,4,4-trifluoro-2-butenenitrile (1c) having a chloro group as a leaving group gave 2,4-di (4-biphenylyl)-2,4-dicyano-l ,5-bis(trifluoromethyl)-3, 6-dithiabicyclo [3.1.0] hexane (4) and 2-(4-biphenylyl)-4,4,4-trifluoro-2-butenenitrile (5). Methyl 2-(4-biphenylyl)-3-chloro-4,4,4-trifluoro-2-butenoate (1d) having an ester group in the place of a cyano group afforded di- [2-(4 biphenylyl)-2-methoxycarbonyl-1-trifluoromethylethyl] disulfide (6). The formation of such sulfur-containing organofluorine compounds except for the oligomeric compound 3 is characterized as the addition of polysulfide anion(s) produced by electroreduction of elemental sulfur, followed by the elimination of the phenylsulfonyl or the chloro group.