A Mild Method for Access to α‐Substituted Dithiomalonates through C‐Thiocarbonylation of Thioester: Synthesis of Mesoionic Insecticides

An efficient method for targeting a variety of symmetrical and asymmetrical α‐substituted dithiomalonates (DTMs) is described, utilizing 1H‐imidazole‐1‐carbothioates as reactive acylating agents and MgBr2⋅OEt2/DBU or LiHMDS for soft or hard enolization conditions of thioesters, respectively. The utility of this methodology was demonstrated through the synthesis of the pyridopyrimidine mesoionic insecticides: triflumezopyrim and dicloromezotiaz. magnified image