Preparation of terminal alkenic esters by an oxidative radical reaction

A general method is described for the conversion of(mono)alkenic esters with the double bond at the n^th C atom to terminal alkenic esters of (n?1) C atoms in length, with the double bond at n?2. Ozonolysis, either in methanol or in light petroleum, is followed by reaction with a mixture of ferrous and cupric salts. Methyl 10-undecenoate, methyl oleate (methyl (Z)-9-octadecenoate) and methyl erucate (methyl (Z)-13-docosenoate) were converted to methyl 8-nonenoate, methyl 7-octenoate and methyl 11-dodecenoate respectively. An improved preparation of 5-hexenoic acid is also described.