Collect. Czech. Chem. Commun. 1998, 63, 378-386

Electroreductive Additions of Aromatic Dichalcogenides to Fluorinated Ethenes

David Dvořáka, Eva Neugebauerováb, František Liškab and Jiří Ludvíka

a J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague 8, Czech Republic
b Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6, Czech Republic


Intermediates and products formed during the electrochemical reduction of diphenyl disulfide (1) add to chlorotrifluoroethene (3) under the formation of 2-chloro-1,1,2-trifluoroethyl phenyl sulfide (5) and the E/Z isomers of 2-chloro-1,2-difluoroethenyl phenyl sulfide (6). The analogous reaction with 1,2-dichlorodifluoroethene (4) led to a mixture of E/Z isomers of 6. Electrochemically reduced diphenyl diselenide (2) reacted with 3 giving rise to 2-chloro-1,1,2-trifluoroethyl phenyl selenide (7) whereas the reaction with 4 does not proceed. Addition of disulfide 1 to 4 gives evidence of the participation of the radical PhS.. With diselenide 2, an analogous radical addition reaction was not observed. This is consistent with other experiments suggesting different mechanisms of reductive cleavage of the S-S and Se-Se bonds and the absence of radicals PhSe. in the latter.

Keywords: Electrochemistry; Diphenyl dichalcogenides; Diphenyl disulfide; Diphenyl diselenide; Chlorofluoroethenes; Electroreductive addition.