A study of 1,5-hydrogen shift and cyclization reactions of an alkali isomerized methyl linolenoate

Abstract Heating a mixture formed by alkali isomerization of methyl linolenoate ( 1 ) produces a complex mixture with the bicyclic hexahydroindenoic esters 4β-(7-methoxycarbonylheptyl)-5α-methyl-2,3,3aα,4,5,7aαhexahydroindene (CL5) and 4β-ethyl-5α-(6-methoxycarbonylhexyl)-2,3,3aα,4,5,7aα-hexahydroindene (CL6) as main components. Similar isomerization reactions of three synthetic model compounds, methyl 9 Z ,13 E ,15 Z -octadecatrienoate ( 2 ), 9 Z ,14 E ,16 E -octadecatrienoate ( 4 ) and 9 Z ,11 E ,15 Z -octadecatrienoate ( 5 ) corroborated the results obtained with alkali isomerized methyl linolenoate.