Acetic anhydride as a versatile carbon source in carbonylation reactions

Acetic anhydride (Ac₂O) is a cheap and easily available chemical feedstock that is widely used as an acetylating or dehydrating agent in organic synthesis. Here, we report Ac₂O as a novel and versatile carbon source in carbonylation reactions. Notably, besides CO, the acetic acid (AcOH), decomposed from the Ac₂O molecule, could participate in the reaction and simultaneously act as a necessary cosolvent. Acetate esters, aldehydes, and carboxylic acids could be produced separately by simply regulating the Pd-catalyzed reaction of olefins, Ac₂O and H₂. Remarkably, the reaction is applicable to various olefins, and high yields (up to 95%) as well as good regioselectivities of the acetate esters and aldehydes could be achieved. The outstanding results of acetate ester synthesis represent a successful and innovative cascade reaction, which demonstrates good atom economy. The mechanism of the reactions, especially the Ac₂O decomposition, has been studied by control experiments and DFT calculations. This work opens a new avenue for carbonylation reactions.