Asymmetric Biomimetic Oxidations of Phenols: The Mechanism of the Diastereo- and Enantioselective Synthesis of Thomasidioic Acid

Enantiopure chiral amidic derivatives of sinapic acid were oxidised withhydrogen peroxide using horseradish peroxidase (HRP) as the catalyst to give thearyltetraline dilignol thomasidioic acid. Trans-diastereoselectivity and enantioselectivity inthe formation of thomasidioic acid was observed. Computational methods show that theenantioselectivity is controlled by the β-β oxidative coupling step, while thediastereoselectivity is controlled by the stability of the reactive conformation of theintermediate quinomethide.