Electrochemical Debromination of 1-Aryl-1,2-dibromo-2-nitropropanes in Dimethyl Sulfoxide

Article abstract of DOI:10.1021/jo00112a031

Electrochemical debromination reactions of erythro-dl-1-aryl-1,2-dibromo-2-nitropropanes 1a-d at a platinum electrode have been investigated by cyclic voltammetry in 0.10 M LiClO4/DMSO.The reactions produced (E)-1-aryl-2-nitropropenes 2a-d in high yields.The cyclic voltammograms were irreversible and the reduction current decrease as the number of cycles increased.The peak potential for the reductions waves are in the range of -0.51 to -0.56 V (vs Ag/Ag(1+)) and show no clear trend with different aryl substituent.The current density increased as the concentration of the substrate increased.The slopes of the plots of log(I/A) vs log are close to unity, indicating unimolecular processes.For all reactions, the Tafel slopes are in the range of 115-125 mV.The logarithm of the ratio i_X/i_H at -0.16 V did not correlate with the Hammett substituent constants.From these results, the mechanism of these reactions is assessed.