Efficient photochemical synthesis of tricyclic keto-indoles

✍ Scribed by Christèle Tietcheu; Christophe Garcia; Daniel Gardette; Denise Dugat; Jean-Claude Gramain

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2002
• Tongue: English
• Weight: 76 KB
• Volume: 39
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570390517

✦ Synopsis

Abstract

Tricyclic keto‐indoles were synthesized by photocyclization of easily obtained enaminones in an electro‐cyclic photochemical reaction. The three methods reported were chosen according to the enaminone structure. The most general procedure using one‐step synthesis was carried out in a benzene‐methanol solution in the presence of sodium methylate. In the case of base sensitive substrates, the best method was photocyclization followed by oxidation. Besides, N‐unsubstituted indoles with a five‐membered ring were prepared by a photolysis reaction. All three methods are efficient and easy to perform.