Synthesis and Properties of Tricyclo2,8>deca-3,5-dien-9-one. A New Entry to the C10H10 Manifold

Article abstract of DOI:10.1021/jo00389a003

Starting from 3,8-cyclodecadiene-1,6-dione bis(ethylene acetal) (4) a 10-step synthesis is described which leads to the title compound 18.It is found that 18 rearranges to tricyclo<5.3.0.0^2,10>deca-3,5-dien-9-one (33) at room temperature.The pyrolysis and photolysis of the tosylhydrazone of 18 and 19 yields the cycloheptatriene derivatives 41 and 42.From the mesylate of the corresponding alcohol of 18 two dihydroazulenes (38 and 39) could be isolated and characterized.In carrying out of the Shapiro reaction with 19 we obtained tricyclo<5.3.0.0^4,8>deca-2,5,9-triene (35).MNDO calculations concerning the possible reaction path of tricyclo<5.3.0.0^2,8>decatriene (2) to 35 suggest a radical mechanism and isobullvalene (34) as an intermediate.