Benzyne from o-Sulphobenzoic Anhydride

The data strongly suggest the formation of benzyne from o-sulphobenzoic anhydride—from the products of its reaction with benzene by 1,2- and 1,4-addition (naphthalene, phenylnaphthalene) and insertion (biphenyl, about four times as much by weight as from benzene alone). The uncondensed gases from the reaction were a 1 1 mixture of sulphur dioxide and carbon dioxide. This, in addition to the other products, indicates that the first step of Path 2, loss of sulphur dioxide, is the dominant primary process. However, the resulting zwitterion, unlike its cationic counterpart in the mass spectrometer, does not go on to lose carbon monoxide it stabilizes itself more easily by losing carbon dioxide... 

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