PdCl2/Bu4NI: An efficient and ligand-free catalyst for the alkoxycarbonylation of organic chlorides

• An active and ligand-free PdCl2/Bu4NI catalytic system was developed.
• Alkoxycarbonylation of various organic chlorides were tested.
• High activity and moderate to excellent yields of esters were obtained.
• The role of Bu4NI was to stabilize Pd catalyst and activate the inert CCl bond.

An active, efficient and ligand-free Pd catalyst system was developed for the alkoxycarbonylation of organic chlorides using PdCl2/Bu4NI catalyst. The influences of various parameters such as solvent, base, ligand and promoter on activity in the alkoxycarbonylation of CH2Cl2 were investigated. Ligand-free PdCl2 with the aid of Bu4NI showed efficient catalytic performance for this inactive transformation, and 87.6% conversion with 67.3% total yield of esters was obtained using 2.5 mol% PdCl2 at 110 °C. Under optimal conditions, chloroacetates, chloracetone, benzyl chloride and even some aryl chlorides can be carbonylated to corresponding esters in moderate to excellent yields. Moreover, the effect of Bu4NI on the reaction was discussed in detail and it was critical in both stabilizing the Pd catalytic system and activating the inert CCl bond in the reaction.

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