One-pot multicomponent synthesis of azaindoles and pyrroles from one molecule of a silicon-tethered diyne and three or two molecules of organonitriles mediated by zirconocene.

A zirconocene-mediated one-pot multicomponent synthesis process leading to the synthesis of pyrrolo[3,2-c]pyridine (5-azaindoles) and pyrrole derivatives has been developed starting from a silicon-tethered diyne and three or two different or identical organonitriles. Pyrrolo[3,2-c]pyridine and pyrrole derivatives with diverse structures and substitution patterns have been highly selectively prepared by this protocol. A wide variety of organonitriles and silicon-tethered diynes, either aliphatic or aromatic with both electron-withdrawing and -donating groups, have been used to afford 5-azaindoles and/or pyrroles in good-to-excellent isolated yields. A key intermediate formed in the Cp(2)Zr(II)-mediated reaction of one (PhC[triple bond]C)(2)SiMe(2), two molecules of iPrCN and one p-tolylCN was characterised by X-ray single-crystal structural analysis, which has allowed us to gain a good understanding of the reaction process.