Palladium-Catalyzed Syntheses of Conjugated Polyenes

Article abstract of DOI:10.1021/jo00155a005

Conjugated trienes have been prepared by the palladium-catalyzed reaction of vinylic bromides with 2,4-pentadienoic acid and its 3-methyl derivative, in the presence of triethylamine.Methyl (E)-3-bromo-2-methylpropenoate also forms conjugated trienes and in some instances also tetraenes when it is reacted with 1,3-dienes under similar conditions.Some loss of stereochemistry in the starting vinylic bromide or, more often, in the diene may occur in the rections presumably because equilibrating ?-allylic intermediates are involved.1,3,5-Hexatriene and 2 equiv of methyl (E)-3-bromo-3-methylpropenoate form orange-red dimethyl (E,E,E,E,E)-2,11-dimethyl-2,4,6,8,10-dodecapentaenedioate in modest yield.