In an aqueous alkaline solution, the exothermic isomerization of quadricyclane derivatives to norbornadiene derivatives catalyzed by cobalt-porphyrin complexes was investigated. By catalytic action of cobalt 5, 10, 15, 20-tetrakis (p-carboxyphenyl) porphyrin (Co- TPPC),'thermally stable and water-soluble quadricyclane derivatives la-1 isomerized to the corresponding norbornadiene derivatives 2a-1 quantitatively and suddenly even at room ...