Novel five-membered ring formation by oxidative photocyclization of 4-(2-arylvinyl)benzo[a]quinolizinium salts

✍ Scribed by Sadao Arai; Hiroe Yoda; Kiyoshi Sato; Takamichi Yamagishi

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2002
• Tongue: English
• Weight: 47 KB
• Volume: 39
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570390230

✦ Synopsis

Abstract

Oxidative photocyclization of 4‐(2‐arylvinyl)benzo[a]quinolizinium salts (6) gave five‐ or six‐mem‐bered rings depending on the aryl substituent. The olefins 6a and 6b with a phenyl or naphthyl substituent resulted in a normal six‐membered ring formation to afford 6a‐azoniapicene and 6a‐azoniabenzo[b]picene salts (7 and 8), respectively. In contrast, the photo‐reaction of pyridyl substituted derivative 6c resulted in novel five‐membered ring formation to yield 3b‐azonia‐5‐(2‐pyridyl)acephenanthrylene salt (10).