Thiourea-Mediated Esterification by Redox Dehydration

The synthesis of carboxylic esters represents a pivotal transformation in organic chemistry owing to their widespread utility in pharmaceuticals, natural products, materials science, and fine chemicals. Traditionally, esterification by redox dehydration required a P^III/P^V process using P^III as the oxygen acceptor. Here we report a novel method of redox dehydration employing thiourea as an [O] acceptor through desulfurization. Using this rapid and operationally simple protocol, a variety of esters and lactones can be easily synthesized from readily available substrates in good to excellent yields.