Iron(III) and copper(II) catalysed transformations of fatty acid hydroperoxides: efficient generation of peroxy radicals with copper(II) trifluoromethanesulphonate
Whereas methyl (9Z,11E,13S)-13-hydroperoxyoctadeca-9,11-dienoate (3) and methyl (9Z,11E,13S,15Z)-13-hydroperoxyoctadeca-9,11, 15-trienoate (4) are converted by FeCl3 dietherate into epoxy alcohols and chloroepoxides, catalytic amounts of copper(II) trifluoromethanesulphonate in the presence of octanoic acid under oxygen efficiently convert the second compound into hydroperoxy dioxolanes and dioxabicycloheptanes, and methyl (5Z,8Z,11Z,13E,15S)-15-hydroperoxyeicosa-5,8,11,13-tetraenoate (15-HPETE methyl ester, 18) into hydroperoxy bisdioxolanes via an 11-peroxy radical.