Acid cyclization of 4-(indol-1-and-3-ylmethyl)-2-cyanopiperidines 5̃ led to the bridged tetracyclic indole-systems 1̃ and 2̃. The required 2-cyanopiperidines 5̃ were prepared by catalytic hydrogenation of 2-cyano-1, 2, 3, 6-tetrahydropyridines 4̃ and by DIBAL reduction of lactams 7̃ followed by cyanide ion addition to the intermediate enamine.