Direct organocatalytic esterification of carboxylic acids and alcohols by redox neutral sulfur(<scp>iv</scp>) catalysis <i>via</i> intramolecularly interrupted Pummerrer intermediates

Design, synthesis, and catalytic activity of new sulfur(IV) based organocatalysts for the direct esterification of carboxylic acids and alcohols is unveiled. The polar nature of the sulfoxide in the phenol-tethered catalyst accelerates the formation of an intramolecularly interrupted Pummerrer intermediate that further facilitates the catalytic esterification reaction <i>via</i> the activation of carboxylic acids.