Direct α‐Acylation of Thioesters With Carbonylimidazolides Toward α‐Substituted Malonate Monothioates and Weinreb‐Type Monoamides

A direct α‐acylation strategy of thioesters for the synthesis of α‐substituted monothiomalonates and β‐thioester‐Weinreb amides is described. Using carbonylimidazolides as acylating agents under LiHMDS‐mediated conditions, the method provides efficient access to a broad range of previously inaccessible derivatives, including α‐aryl analogs, in high yields without stoichiometric coupling reagents. The utility of the approach is demonstrated through gram‐scale reactions and diverse downstream functionalizations .