COMPETITIVE REACTIVITY OF VINYLCHALCOGENYL RADICALS IN THEIR REACTIONS WITH ACETYLENE

The reactivities of vinylthiyl and vinylselenyl radicals generated by high temperature gasphase reactions of acetylene with diethyl disulfid e and diethyl selenide, respectively, were compared. The co-pyrolysis of a mixture of these reagents at 410-510 degrees C results in a mixtu re of thiophene and selenophene. The vinylselenyl radical is more reac tive; in addition, it appears to stabilize vinylthiyl radicals. Owing to this, co-thermolysis of diethyl disulfide, diethylselenide, and ace tylene at 510 degrees C allows one to obtain simultaneously thiophene and selenophene in 91.0 and 92.5% yields, respectively.