Direct carbonylation of the C(sp3)—Cl bond remains a challenging transformation in the chemical industry. The usual use of precious metals, the high cost of ligands, and the lack of recyclability… Click to show full abstract
Direct carbonylation of the C(sp3)—Cl bond remains a challenging transformation in the chemical industry. The usual use of precious metals, the high cost of ligands, and the lack of recyclability of catalysts make their industrial application on a large scale impossible. A ligand‐free cobalt‐based catalyst for the alkoxycarbonylation of chloroacetates to dialkyl malonates, which are important industrial intermediates, is reported here. This catalyst uses an extremely inexpensive precursor, CoCO3, with a very low catalyst loading (0.5 mol%) to achieve product yields of up to 99% with nearly 100% chemoselectivity. Solvents and previously essential phase transfer agents are not needed. Most importantly, the catalyst can be easily recycled without losing its activity and selectivity. Over 95% product yield is achieved even after 8 recycles. The feasibility of this system is demonstrated through 14 examples of the alkoxycarbonylation reaction. Fourier transform infrared spectroscopy investigations identified the active cobalt species as [Co(CO)4]−. As the first recyclable cobalt‐based catalyst, this ligand‐free system has great potential for large‐scale industrial transfer.
               
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