Synthesis of condensed heteroaromatic compounds by palladium-catalyzed oxidative coupling of heteroarene carboxylic acids with alkynes

Org Lett. 2009 Jun 4;11(11):2337-40. doi: 10.1021/ol900736s.

Abstract

The palladium-catalyzed oxidative coupling of indole-3-carboxylic acids with alkynes effectively proceeds in a 1:2 manner accompanied by decarboxylation to produce the corresponding 1,2,3,4-tetrasubstituted carbazoles, some of which exhibit solid-state fluorescence. Pyrrole-, benzofuran-, and furancarboxylic acids also undergo the decarboxylative coupling to afford highly substituted indole, dibenzofuran, and benzofuran derivatives, respectively.