The Kinetics of Photochemical Deconjugation Reactions of Methyl Geranate

Article abstract of DOI:10.1016/S0040-4020(01)86011-7

The photochemical transformations of methyl geranate are analyzed in terms of the depedence of quantum yield upon base, 1,2-dimethylimidazole, concentration.The dependence of quantum yield of deconjugated esters methyl (3Z)-3,7-dimethyl-3,6-octadienoate (12), methyl 3-methylene-7-methyl-6-octenoate (13), and methyl (3E)-3,7-dimethyl-3,6-octadienoate (14) and the ratio of (13)/(12) and (13)/(14) upon base concentration, as well as the dependence of the ratios (methyl 2-isopropenyl-5-methylcyclopentanecarboxylate (15): deconjugated ester) (10)/(12), (10)/(13) and (10)/(14) upon the reciprocal of the base concentration, are consistent with relative rate constant ratios for (<1,5>sigmatropic shift)/(dienol deprotonation) for photodienols 15, (precursor of 13), 17 (precursor of 12) and 19 (precursor of 14), of 72, 1.0 and 85.