Alkyl and Aryl Thioester Synthesis via N-Heterocyclic Carbene-Catalyzed α-Thio Aldehyde Rearrangement

We have developed a highly atom economic transformation to provide a thioester. The N-heterocyclic carbene-catalyzed rearrangement of α-thio aldehydes affords thioesters in good yields. This reaction exhibits a broad substrate scope and is applicable to aldehydes bearing either alkylthio or arylthio groups. The optimal combination of catalyst precursor and base is highly dependent on the nature of the S substituent in the starting α-thio aldehyde.