Cobalt-Catalyzed [2+2+2] Cycloadditions of Alkynyl Yndiamides with Nitriles

Herein is described a convenient cobalt-catalyzed [2+2+2] cycloaddition of alkynyl yndiamides with nitriles. This regioselective reaction provides access to 39 novel valuable 2,3-dihydro-1<i>H</i>-pyrrolo[2,3-<i>c</i>]pyridin-7-amine or (1,2,3,4-tetrahydro-1,7-naphthyridin-8-yl)-9<i>H</i>-carbazole derivatives. These highly substituted pyridines are important building blocks in medicinal chemistry. The process is eco-friendly since the cycloaddition is conducted in a green solvent with a non-noble transition metal catalyst.