Synthesis and Transformations of 5-Cyano-2,2,8,8,12,13,17,18-octamethylisobacteriochlorin

A model substrate for studies in the hexahydroporphyrin series, i.e. the title compound (1) having C2v symmetry, has been prepared by a multistep de‐novo synthesis from a cyanosubstituted thiolactam. Catalytic hydrogenation of (1) affords the highly O2‐sensitive 2,3,7,8,15,24‐hexahydro derivative; attempts to incorporate metal ions into this species lead to complexes of the 1,2,3,7,8,20‐hexahydro isomer.