Cyclic Iodonium Ylide Unlocked Pd-Catalyzed α-Acyloxylation of Cyclic 1,3-Dicarbonyls with Carboxylic Acids

To date, a general approach for the direct α-acyloxylation of cyclic 1,3-dicarbonyls remains challenging. Herein, we report a Pd-catalyzed α-acyloxylation of cyclic 1,3-dicarbonyl-derived hypervalent iodine compounds with highly abundant carboxylic acids. Our approach utilizes a commercially available Pd(OAc)₂ catalyst, which exhibits mild reaction conditions, scalability, operational simplicity, and robustness against moisture and air. Importantly, our approach eliminates the need for excess carboxylic acids (only 1 equiv) and the use of explosive peroxides and is compatible with diverse complex substrates (e.g., glycyrrhetinic acid and celastrol). The power of this method is further demonstrated through significantly simplifying a previous synthesis.