Radical annulations and cyclisations with isonitriles: the fate of the intermediate imidoyl and cyclohexadienyl radicals

D Nanni, P Pareschi, C Rizzoli, P Sgarabotto, A Tundo

Index: Nanni, Daniele; Pareschi, Patrizia; Rizzoli, Corrado; Sgarabotto, Paolo; Tundo, Antonio Tetrahedron, 1995 , vol. 51, # 33 p. 9045 - 9062

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Citation Number: 89

Abstract

The reaction of 4-methoxyphenylisonitrile with phenylacetylene and AIBN produces a novel cyclopenta-fused quinoxaline through addition of 2-cyanoprop-2-yl radical to the alkyne; the resulting vinyl radical attacks isonitrile to afford an imidoyl radical, which gives rise to a tandem 5-exo, 6-endo cyclisation. The whole process entails a new example of a rare 4+ 1 radical annulation. The cyanopropyl radical can also attack isonitrile to yield small ...