A Novel Synthesis of 2,6‐Diolefinic Esters: Ethyl and methyl trans‐2,cis‐6‐dodecadienoate, two Bartlett pear constituents

Ethyl and methyl trans ‐2, cis ‐6‐dodecadienoate, two Bartlett pear constituents, have been prepared by a novel two‐step synthesis: 1,6‐addition of lithium di‐ cis ‐1‐heptenylcuprate to ethyl or methyl trans ‐2,4‐pentadienoate gave exclusively the 3,6‐diolefinic esters, which were isomerized to the desired 2,6‐diolefinic esters. The double‐bond geometry of the vinyl unit is retained during the addition step.