Laser-Induced Cycloadditions: The Carvone Photoisomerisation

Article abstract of DOI:10.1021/jo00137a017

Laser flash photolysis of carvone yields triplet carvone.The lifetime is 75 ns in ethanol and 47 ns in cyclohexane.The photoisomerisation reaction induced by UV pulsed lasers in the 350-nm range (XeF, 350 nm; YAG (third harmonic), 353 nm) gives carvone-camphor and trace amounts of 1-exo,5-dimethyl-syn-2-<(ethoxycarbonyl)-methyl>bicyclo<2.1.1>hexane.Photolysis with a CW laser, in the same wavelenght region (Kr ion, 350.7- and 356.5-nm lines), results in a different product distribution.The differences are explained tentatively in terms of multiphonic UV photolysis.