Photochemical Reactions of Bicyclooctadienons

Article abstract of DOI:10.1021/jo01299a030

A series of spirooxirano-substituted bicyclo<2,2,2>octadienons have been prepared by Diels-Alder addition of dimethyl acetylenedicarboxylate to 2,4-cyclohexadienones, and their photochemistry was investigated.Upon direct exitation, they were found to aromatize by elimination of 2-carbonyloxirane which was trapped by ethanol to give ethyl glycidate.The acetophenone-sensitized reaction of bicyclooctadienones gave tricyclic isomeres whose formation by regiospecific di-?-methane rearrangement is discussed.