“…Pericàs and co-workers found a procedure yielding quantitatively the desired product 382 by oxidizing bis( t -butylthio)acetylene ( 381 ) with m CPBA in chloroform (Scheme ) . Bis( t -butylsulfonyl)acetylene, the structural properties of which could even be elucidated by X-ray analysis, was widely used as a highly reactive dienophile in Diels−Alder reactions ,− and as alkyne component in highly electrophilic CpCo(monoalkyne) complexes. − Also bis(arylsulfonyl)acetylenes 385 and 386 were synthesized; however, a neutral oxidizing agent, such as dimethyldioxirane (DMDO), was necessary to achieve high yields (Scheme ); the corresponding products 385 and 386 could not be isolated without decomposition …”