2,3-dihydro-3-oxo-2-phenyliodonium-benzo[b]thiolenide-1,1-dioxide: Synthesis, decomposition and Cu-catalyzed thermal reactions.

Iodonium ylide 4 was prepared in 93% yield from the reaction of beta-ketosulfone 3 with phenyl iodosyl bis(trifluoroacetate). Although insoluble in most solvents, ylide 4 was readily soluble in a mixture of CH2Cl2/ ethanol (1:1), yielding trimer 5 quantitatively. Upon reaction with various heteroatom nucleophiles the new ylides 7 were isolated, while reaction with CS2 and thiobenzophenones yields thione 10 and alkenes 14 respectively. Furthermore 4 reacts with various alkenes 15 affording cyclopropanes 16 in moderate yields as well as with alkyne 17 affording furan 18. (C) 1997 Elsevier Science Ltd.