A Concise Synthesis of the 2,3-Dimethylene-1,4-methano-1,2,3,4-tetrahydronaphthalene and its Reaction with Singlet Oxygen

Article abstract of DOI:10.1016/S0040-4020(01)85643-X

Palladium-catalyzed carbomethoxylation of benzonorbornadiene (7) yielded dimethyl-1,4-methano-1,2,3,4-tetrahydronaphthalene-2,3-dicarboxylate (9) which was transformed in three steps into 2,3-dimethylene-1,4-methano-1,2,3,4-tetrahydronaphthalene (4) in a high yield.Reaction of 4 with singlet oxygen resulted in the formation of epoxy-endoperoxide (12).X-ray crystallographic analysis demonstrated that epoxide ring is exo as methylene bridge.For the first time, the epoxy-endoperoxide formation from the "one pot" reaction of a diene with singlet oxygen was observed.The epoxy-endoperoxide formation mechanism was discussed.CoTTP (Cobalt(II)tetraphenylporphyrin) catalyzed rearrangement of epoxy-endoperoxide gave hydroxy-aldehyde (13) which was oxidized into dialdehyde (14).