Acylation of phenols to phenolic esters with organic salts

Abstract

Effective valorization of lignin to produce high-value chemical products can enhance the productivity and profitability of biorefineries. The upgrading of lignin derived molecules such as phenols into high-value commodity chemicals is an effective way to combine low environmental footprint with significant economic benefits. Selective O-acylation of phenolic compounds to produce phenolic esters which possess diverse applications is very attractive. Herein, we report an efficient, convenient one-pot method for selective O-acylation of phenols at room temperature in air. For the first time, abundant, safe, stable organic salts are used as acylating reagents. The reaction was mediated by diethylaminosulfur trifluoride (DAST) which simultaneously acted as an activator for phenols and deoxyfluorination reagent for organic salts. Phenolic esters were almost quantitatively produced from a diverse range of phenols including lignin-derived substrates. This new method is significantly distinct from existing routes, and the scientific discovery about activation of phenolic hydroxyl groups is instructive for exploration of new chemical reactions.