Abstract: The photorearrangement of anti-and syn-2-chlorobenzobicyclo [2.2. 2] octadien-3- one(1 and 2) in methanol gave naphthalene, methyl 1-naphthylacetate (6) and 7- carbomethoxy-2, 3-benzonorcaradiene (5). The photolysis of anti-2-chloro-bicyclo [2.2. 2] octen-3-one (3) gave the 7-carbomethoxynorcarene (7) in 55% yield. The corresponding syn- chloro ketone (4) did not rearrange to the norcarene product illustrating the ...