Recyclable picolinamide-derived ligand-controlled branched-selective hydroesterification of alkynes with alcohols and phenols†

Hydroesterification of alkynes is a crucial synthetic transformation, enabling the formation of esters directly with high atom economy. Recent advancements have centered on improving the reaction's selectivity, efficiency, and environmental sustainability, particularly through the innovation of ligands and catalysts, making the process more practical for industrial applications. Herein, we report a highly selective and efficient hydroesterification of alkynes using a novel recyclable ligand, accommodating a wide range of alkyne substrates as well as various alcohols and phenols. The reaction proceeds under mild conditions, affording the desired esters in high yields with excellent regioselectivities. A notable feature of this method is the recyclability of the ligand, which can be recovered and reused multiple times without significant loss of activity or selectivity. Mechanistic studies revealed that palladium was well dispersed on the nanoscale and was essential for this sustainable hydroesterification process.