A New Facet of Azatriene Reactivity: A Short Cut to 5‐Amino‐3‐methyl‐4‐(1H‐pyrrol‐1‐yl)thiophene‐2‐carboxylates and 5‐Amino‐3‐methyl‐4‐(1H‐pyrrol‐1‐yl)thiophene‐2‐carbonitriles

Abstract

An simple and expedient approach to highly functionalized tetrasubstituted thiophenes from readily accessible starting materials [(1H‐pyrrol‐1‐yl)allene, isothiocyanates, and alkyl 2‐bromoacetates or 2‐bromoacetonitrile] has been developed. The method is based on the one‐pot synthesis and fast in‐situ cyclization of alkyl 2‐{[2‐(1H‐pyrrol‐1‐yl)buta‐2,3‐dienimidoyl]sulfanyl}acetates or cyanomethyl 2‐(1H‐pyrrol‐1‐yl)buta‐2,3‐dienimidothioates (1‐aza‐1,3,4‐trienes) to give previously unknown thiophene‐2‐carboxylates and thiophene‐2‐carbonitriles, respectively, both bearing pyrrole substituents.