Electrochemical reduction of arenesulfonyl cyanides

Abstract

Abstract. Benzenesulfony 1 cyanide and six pora-substitution products were reduced electrochemically at a dropping mercury cathode, in DMF as solvent. A linear Hammett relation between the half-wave potentials of the first reduction wave and the 0,-values was observed. This suggests the reduction mechanism being andlogous for all molecules studied. The half-wave potentials could not be correlated with the electron affinities of these molecules, since for all compounds the first reduction wave is irreversible, due to the formation of mercurous intermediates. Performing electrochemical reduction within the ESR cavity spectra were obtained in some cases. For p-cyanobenzenesulfonyl and p-nitrobenzenesulfonyi cyanides these ESR spectra could be analysed and were assigned to the p-cyanobenzenesulfonyl and p-nitrobenzenesulfonyl dianion radicals, respectively. Prolonged reduction ofp-nitrobenzenesulfonyl cyanide in DMF yields two additional ESR spectra, which could be assigned to the p-nitrobenzenesulfinyl and p-nitrobenzenesulfenyl dianions. So the SO, group is reduced selectively in presence of the NO, group.

Eosin-Mediated Alkylsulfonyl Cyanation of Olefins

“…In the absence of 1a , only the transient absorption of 3 ET* (λ max = 440 nm) could be detected. The lack of electrochemical data for RSO 2 CN led us to estimate the redox potential of several sulfonyl cyanides using cyclic voltammetry (Figures S7 and S8, Table S3). Alkylsulfonyl cyanides exhibit highly negative irreversible reduction potentials, rendering direct electron transfer from EY* very unlikely.…”