Transition metal-catalyzed reactions in organic synthesis, part 10. Cobalt-mediated regioselective synthesis of substituted tetrahydroquinolines

A regioselective synthesis of polycyclic substituted pyridines is reported. Key step is the cobalt-catalyzed intramolecular cyclization of diynenitriles, tethered by a silicon oxygen bond. Subsequent opening of the Si-O ring led then to the related tetra-hydroquinolines.