Effect of Triplet-State Sensitization on Inter- and Intramolecular 2+2 Photocycloadditions of 2,5-Cyclohexadien-1-ones

Article abstract of DOI:10.1021/ja00009a039

The intramolecular 2+2 photocycloadditions of 4-carbomethoxy-4-(4'-phenyl-3'-butenyl)-2,5-cyclohexadien-1-ones 5a, 5b, and 12 give 6-phenyltricyclo<5.2.1.0^5,10>dec-2-en-4-ones 6 and 13 in excellent yields.In contrast to 4-(3'-butenyl)-4-carbome