A novel type of spiro compound formed by oxidative cross coupling of methyl sinapate with a syringyl lignin model compound. A model system for the β-1 pathway in lignin biosynthesis

Abstract

Oxidative coupling of methyl (E)-sinapate with 1-(4-hydroxy-3,5-dimethoxyphenyl)ethanol, a syringyl lignin model compound, was carried out with hydrogen peroxide catalyzed by horseradish peroxidase. The main product was a cyclohexadienone spiro compound of a novel type. Mild acidolysis caused the loss of one side chain and yielded a dimeric compound with a 1,2-diarylpropane structure. This is the first example of the formation of this structural type by oxidative coupling in vitro.