K2CO3-Catalyzed Synthesis of 2,5-Dialkyl-4,6,7-tricyano-Decorated Indoles via Carbon-Carbon Bond Cleavage.

We describe a novel method to synthesize 2,5-dialkyl-4,6,7-tricyanoindole derivatives from a base-catalyzed reaction of 1,3-diketones with fumaronitrile. The reaction proceeds by the condensation of two molecules of fumaronitrile and one molecule of 1,3-diketone in a remarkable process that involves the cleavage of one C(sp3)-C(sp2) bond in 1,3-diketones and the formation of one carbon-nitrogen bond and four carbon-carbon bonds to construct both the aryl and pyrrole rings of the indole in one step.