Abstract
The monohydroperoxides obtained by chlorophyll-catalysed oxidation of methyl oleate are shown to have the hydroperoxide group in an α position to a trans double bond. The evidence is obtained from infrared and proton magnetic resonance spectra, the latter involving spin-decoupling and calculation of theoretical spectra. Aerial oxidation of methyl linoleate gives only conjugated diene isomers. Chlorophyll-catalysed oxidation gives conjugated dienes, but also products with isolated double bonds. There is no evidence for any product with a single carbon atom between the two double bonds.