Incorporation of catechyl monomers into lignins: lignification from the non-phenolic end via Diels–Alder cycloaddition?

Abstract

Catechyl monomers 1-electron-oxidize and undergo radical coupling to produce benzodioxane units in lignin. Derived o-quinones undergo Diels–Alder reactions giving oxatricyclo and new benzodioxane products, but does this occur in lignification?.