The Argon Laser-Jet Initiated, Multiple-Photon (Reluctant), Electrocyclic Ring Opening of 10,10-Diphenyl-9-(10H)-phenanthrenone: A Carbene and Biradical Modeling Study.

Article abstract of DOI:10.1016/S0040-4039(00)73510-6

While 10,10-diphenyl-9-(10H)-phenanthrenone (1) is inert under conventional irradiation conditions, it undergoes decarbonylation under high-intensity argon laser-jet conditions to form 9,9-diphenylfluorene (3) and the cycloheptatriene 4.Molecular modeling studies indicate that 3 arises from collapse of the singlet carbene ¹5 and the triene 4 from the triplet carbene ³5.