Abstract The reaction of methyl 4-bromobut-2-enoate and silver has been reinvestigated and the coupled product shown to consist of dimethyl octa-trans-2, trans-6-dienedioate (45%), dimethyl 5-vinylhex-trans-2-enedioate (53%), and dimethyl 2, 3-dimethylsuccinate (2%). The second constituent is found to undergo isomerization during hydrolysis. None of the isomeric cis-dienes were detected in the coupled product. Coupling does not appear to proceed via ...