ARYNE FORMATION FROM 1-(2'-CARBOXYARYL)-3,3-DIMETHYL TRIAZENES

A study of the decomposition of 1-(2'-carboxyphenyl)=3,3-dimethyltriaz ene and the tetrabromo-and tetrachloro- analogues showed that the aren ediazonium-2-carboxylates were intermediates in the formation of the c orresponding arynes: the 1-(2' -carboxyletrahalophenyl)-3,3-dimethyltr iazenes are stable precursors that enable cycloaddition reactions of t he tetrahalobenzynes to be carried out in acceptable yields using subs trates such as N-methylpyrrole, p-xylene and m-dimerhoxybenzene.