Alkynes Hydration in Three-Component Double-Acidic Deep Eutectic Solvents.

In this work, a sustainable method for the hydration of both terminal and internal alkynes is presented, affording the corresponding ketones with complete Markovnikov regioselectivity. The key advantage of this approach lies in the use of recently developed three-component, double-acidic deep eutectic solvents (DESs), designed by our research team, which act as triple-active media-simultaneously serving as solvents, reagents, and catalysts. The reaction setup is straightforward and can be carried out under conventional or dielectric heating, typically providing the desired products in good to excellent yields. For terminal alkynes, microwave heating further enhances the sustainability of the process by a significant reduction of reaction times. The reusability of the reaction medium is demonstrated through recycling experiments, while the calculation of two green metrics (sE-factor and EcoScale) highlights the environmental benefits of this strategy.