Photochemical behaviour of bridged compounds. Part II. Photolytic and some ground state reactions of carbonyl-bridged anhydrides and their decarbonylation products
7-Oxonorborn-2-ene-5,6-dicarboxylic anhydrides (I) and cyclohexa-1,3-diene-5,6-dicarboxylic anhydrides (II), with various substituting or fused groups, give substituted benzenes (III) in substitution-dependent yields when irradiated at 2537 Å. A possible rationale for the photolytic decarbonylation is discussed. Some synthetic and ground state reactions of the systems studied are also described.