Microwave-assisted direct amidation of thioesters: a green approach

The direct amidation of thioesters represents an essentially nonclassical route in the synthesis of amides, frequently encountering limitations due to poor compatibility between thioester and amine structures as well as poor atom economy. Herein, we describe a green, efficient and microwave-assisted protocol that not only facilitates high-yielding amide bond formation but also converts the sulfur-containing byproducts into valuable disulfides, significantly enhancing the atom economy. Mechanistic studies establish two concurrent pathways: acyl nucleophilic addition-elimination and oxygen-mediated radical oxidation of the sulfur group. Notably, the protocol has been successfully applied to the synthesis of 64 amides (including difluoromethyl amides and β-mercaptoamides) and ten disulfides with moderate to excellent yields and good functional group tolerance. This work provides a novel and sustainable alternative to traditional amide synthesis methods, offering significant potential for applications in pharmaceutical and materials chemistry.