Methyl 12-oxo-octadec-9-cis-enoate gave methyl 9, 12-epoxyoctadeca-9, 11-dienoate when treated with zinc or cadmium in the presence of di-iodomethane and 1, 2-dimethoxyethane under concomitant ultrasonic irradiation, while under similar conditions copper caused cyclopropanation across the ethylenic bond in methyl oleate and ricinoleate.
