PHOSPHONIUM SALTS AND PHOSPHORANES .5. THERMAL AND ELECTRON-IMPACT INDUCED FRAGMENTATION OF HETEROAROYLMETHYLENETRIPHENYLPHOSPHORANES

A modification of Trippett's pyrolysis of aroylmethylenephosphoranes provides a general procedure for the synthesis of five-membered heteroarylethynes. The electron-impact induced fragmentation of the phosphoranes also produced ions corresponding in mass to the ethynes, but metastable ion data indicate that the extrusion of the ethyne follows the initial loss of H. from the molecular ion.