Chlorocobaloxime complexes featuring substituted pyridine as an axial ligand have been successfully employed as catalysts for the hydration of terminal alkynes to their corresponding methyl ketones in good to excellent yields under ambient reaction conditions.

Abstract

The mild reaction conditions, coupled with the cost-effective and readily available nature of cobaloxime complexes, offer a promising solution to the current challenges in alkyne hydration. These complexes exhibit excellent bench stability and can be easily synthesized in large quantities, making them ideal catalysts for the efficient conversion of alkynes to carbonyl compounds, which have numerous industrial applications. A series of chlorocobaloxime complexes featuring substituted pyridine as an axial ligand have been synthesized and characterized. These complexes have been successfully employed as catalysts for the hydration of terminal alkynes to their corresponding methyl ketones under ambient conditions, affording good to excellent yields. The reaction tolerates a wide range of functional groups, demonstrating broad substrate scope. Notably, the catalyst can be recovered and reused with minimal loss of activity, highlighting its practical utility. The scalability of the approach has been further validated through gram-scale reactions.