Thiocarbonyl Ylide Intermediates Generated by Deprotonation of 2-Phenacylthio- and 2-(p-Bromophenacylthio)-1,3-dithiolylium and 2-(p-Bromophenacylthio)-1,3-dithiolanylium Bromides

Article abstract of DOI:10.1246/bcsj.53.2281

2-(p-Bromophenacylthio)-1,3-dithiolynium bromide, when treated with triethylamine, gave 2-(p-bromophenacylidene)-1,3-dithiole (17percent) and bis-<(p-bromobenzoyl)(1,3-dithiol-2-ylidene)methyl>disulfide (72percent).Treatment of 2-phenacylthio-1,3-dithiolylium bromide with triethylamine also gave similar results.On the other hand, 2-(p-bromophenacylthio)-1,3-dithiolanylium bromide yielded 1-(p-bromophenyl)-2-(1,3-dithiolan-2-yl)-2-thioxoethanone (12percent) in addition to 2-(p-bromophenacylidene)-1,3-dithiolane (49percent) contrary to the reported results.These results can best be rationalized by 1,3-cyclization of thiocarbonyl ylide intermediates to the valence tautomeric episulfides.