Synthesis of monomethyl 5,5′-dehydrodiferulic acid

Abstract

Synthesis of the internal standard reference compound monomethyl 5,5′-dehydrodiferulic acid is described. The synthetic scheme relies on a selective monomethylation of the known compound 5,5′-dehydrodivanillin followed by elaboration into the dehydrodiferulic framework through a dual Horner–Emmons–Wadsworth reaction with methyl diethylphosphonoacetate. Saponification of the ester functionalities provided the target monomethyl 5,5′-dehydrodiferulic acid in 49% overall yield from 5,5′-dehydrodivanillin.