A number of unanticipated transformations were observed when various 2,5-diphenyl-1,4-dithiin sulfones were treated with sodium aside. These include a fragmentation to give 1,2-dicyano-1,2_diphenylethene, the formation of 2,5-diphenyl-l,(t-thiazinel,l-dioxide, and the rearrangement of 3-bromo-2,5-diphenyl-1,4-dithiin-l,l-dioxide to its 2-bromo-isomer. Possible mechanism for these unusual reactions are discussed.
In conjunction with continuing studies of vinyl azides capable of undergoing thermolysis 1 to zwitterionic species (zwittazido cleavage) , we report here an investigation of the reactions of variously substitutedderivatives of1,4-dithiin sulfones with sodium azide. Because of the structural similarity of azide derivatives in this series to azidoquinones, analogous thermolysis pathways were expected, but not realized. Initial studies involved the reaction of 2,5-dibromo-3,6-diphenyl-1,4-dithiin-1,1,4,4,-tetraoxide (la)2 with sodium azide in HMPA. It was anticipated that this would result in the corresponding 2,5-diazido derivative 2a and that this would undergo fragmentation at elevated temperatures to give two equivalents of c&ophenylsulfene. Such a prediction was based upon the observation that 2,5-diazido-3,6-diphenyl-1,4-bensoquinone cleaves