NEW SKELETAL REARRANGEMENTS VIA A CONSTRAINED CYCLOPROPYLDICARBINYL DIRADICAL GENERATED IN THE PHOTODECARBONYLATION OF 2,4-DIPHENYLTETRACYCLO2,4.03,7>DECA-9-ENE-6,8-DIONE

Article abstract of DOI:10.1016/S0040-4039(00)82230-3

Photodecarbonylation of the title diketone (1) gave 3,3a-diphenyl-3a,7a-dihydroindenone (2), 1,4-diphenylcyclooctatetraene (3), and 1,6-diphenylcycloheptatrien-7-ylketene (4).The reaction pathways are discussed on proposing intermediates of 1,2-diphenyltetracyclo<4.3.0.0^2,9.0^5,8>non-3-en-7-one (11) and 1,3-diphenyltricyclo<5.2.0.0^2,9>nona-3,5-dien-8-one (13).Ring expansion of 1 to a 6-membered oxacarbene (17) was also observed.