Syntheses of heterocyclic compounds. Part XXIV. Cyclisation studies with ortho-substituted arylcarbene and arylnitrene precursors

Thermal and photolytic decompositions of the tosyl hydrazones of o-dialkylamino-substituted benzaldehydes yield indolines. The scope and mechanism of this cyclisation have been explored. Moreover, benzaldehyde tosylhydrazones with o-alkoxy-, o-thioalkyl-, and o-phosphonate substituents as well as the corresponding diazoalkanes were pyrolysed and photolysed. The products from these carbene precursors were compared with those obtained from the analogous nitrene precursors [i.e. ArN3 or ArNO2+(RO)3P].