Cerium(III) chloride-promoted chemoselective esterification of phenolic alcohols

A mild and operationally simple method for the chemoselective esterification of phenolic alcohols is described. The reaction overcomes the tyranny of protection, and capitalizes on the activation of acyl halides with cerium(III) chloride to selectively esterify alcohol hydroxyls in the presence of phenolic ones. The generality of the reaction was demonstrated with a series of phenolic alcohols of dietary relevance (vanillol, hydroxytyrosol, epicatechin), providing an expeditious entry into a series of compounds of relevance for biomedical research, some of which previously available only by enzymatic methods.