On regioselectivity of the reaction of p-quinone methides with p-hydroxybenzyl alcohols

Abstract

1H NMR analysis of the reaction of lignin model p-quinone methides with aliphatic alcohols, phenols and p-hydroxybenzyl alcohols in chloroform solution has demonstrated a pronounced predominance of non-cyclic benzyl alkyl ethers over benzyl aryl ethers in the mixture of products, as a result of faster addition of alcohols than phenols. In the case of the simplest p-quinone methides, the only competing reaction seems to be a stereoselective isomerization into E-p-hydroxystyrenes.