Thermal ring enlargement of aromatic cyclopentadienylidene iminyl radicals. Intramolecular radical addition to the N atom of nitriles results in high yields of aza- …

J Hofmann, K Schulz, G Zimmermann

Index: Hofmann, Joerg; Schulz, Kathrin; Zimmermann, Gerhard Tetrahedron Letters, 1996 , vol. 37, # 14 p. 2399 - 2402

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Citation Number: 5

Abstract

It has been demonstrated that ketiminyl radicals, formed at high temperatures (1000° C, 0.3 s) in oxygen-free nitrogen from phenylhydrazones of benz-anellated cyclopentadienones (fluorenone (9a), methanophenanthrenone (9b)), yield into phenanthridine (8a) and benzo [lmn]-phenanthridine (8b) in yields> 60%. The results point to a predominant addition of intermediately generated phenyl type radicals 5 to the N atom of the nitrile groups ...