An Easy Route to Conjugated (all E) Tetraene Compounds via Disilyl Derivatives Exemplified by beta-Parinaric Acid Methyl Ester

The synthesis of conjugated (all E) tetraene compounds has been easily achieved in a few steps by electrophilic substitution reactions between (1E,3E)-1,4-bis(trimethylsilyl)-1,3-butadiene (1a) or (1E,3E,5E)-1,6-bis(trimethylsilyl)-1,3,5-hexatriene (1b) and acyl chlorides in the presence of aluminum trichloride, followed by reduction and dehydration reactions. As a representative example, the synthesis of the methyl ester of beta-parinaric acid 6 [methyl (9E,11E,13E,15E)-9,11,13,15-octadecatetraenoate], an interesting fluorophore, is reported