

(AZA)INDOLIZINES AND ETHYL PROPIOLATE: [8+2] AND [1,10] CYCLIZATIONS

Abstract
(Aza)indolizines reacted with ethyl propiolate regioselectively forming (aza)[2.2.3]cyclazines. The Sonogashira reaction of 5-iodo(aza)indolizines and acetylenes led to 5-ethynyl(aza)indolizines. In the case of indolizine derivative the by-product was ethynylcyclazine. The structures of [2.2.3]cyclazines were proved by X-ray structural analysis.
Keywords
[8+2] cycloaddition; indolizine; imidazo[1,2-a]pyridine; Sonogashira reaction
Latvian Institute of Organic Synthesis - Aizkraukles iela, 21, Riga, LV-1006, Latvia - hgs@osi.lv