123285-89-2Relevant academic research and scientific papers
Photochemistry of Some Extended ?-Systems: Type A and Aryl Rearrangements of Systems with Extended Conjugation Related to Cyclohexadienones and Cyclohexenones. Mechanistic and Exploratory Organic Photochemystry
Zimmerman, Howard E.,Lamers, Paul H.
, p. 5788 - 5804 (2007/10/02)
6,6-Diphenyl-2(6H)-naphthalenone and 5,6,6-triphenyl-2(6H)-naphthalenone were sinthesized as extended relatives of 4,4-diphenylcyclohexadienone and their photochemistry was investigated.In the case of the diphenylnaphthalenone, irradition resulted in a regioselective phenyl migration and formation of 5,6-diphenyl-2-naphthol whether the photolysis was in methanol or in benzene.Irradiation of the triphenylnaphthalenone in methanol or isopropyl alcohol afforded a product in which one molecule of solvent and one molecule of molecular oxygen were incorporated.Photolysis in acetonitrile led instead to a tricyclic photoproduct in a process reminiscent of the type A rearrangement of 2,5-cyclohexadienones.This tricyclic photoproduct itself was photochemically reactive and rearranged regioselectively to afford 5,7,8-triphenyl-2-naphthol.By trapping, a tricyclic zwitterion was shown to play a role in the rearrangement of the triphenylnaphthalenone.The photochemystry of both naphthalenones was shown by quenching to result from triplet excited states.Lack of reactivity on sensitization suggested the photochemystry derives from Tn.The quantum efficiencies were shown to be lower and the triplet reaction rate slower in the comparison with the monocyclic 4,4-diphenylcyclohexadienone.Finally, enone analogues were investigated.Both 6,6-diphenyl-4,4a,5,6-tetrahydro-2(3H)-naphthalenone and 6,6-diphenyl-4,4a,5,6,10,10a-hexahydro-2(3H)-anthracenone were synthesized.Only the former was reactive; phenyl migration resulted in formation of four stereoisomeric tricyclic ketones whose structures were established by X-ray analysis.For all of the various reactions, mechanisms are provided and discusseed along with MNDO-CI computations.
