Formation of p‐vinylguaiacol oligomers in the thermal decarboxylation of ferulic acid

Abstract p‐Vinylguaiacol synthesized by decarboxylation of ferulic acid [3‐(4‐hydroxy‐3‐methoxyphenyl)propenoic acid] with copper powder in refluxing quinoline was accompanied by oligomers. A dirtier and a trimer were isolated and identified as linear oligomers coupled head‐to‐tail. The trimer was a I:I mixture of (R,R + S,S) and (R,S + S,R) forms, according to its 220 MHz NMR spectrum.