Green Synthesis of Nitriles from Biomass-Derived Aldehydes by Evoking Intrinsic Cooperative Effects of Ionic Liquids

Nitriles are important organic synthesis intermediates, but producing nitriles from renewable feedstocks with simple, efficient, and green catalytic systems is still challenging. Herein, we report a domino-type multi-interaction synergetic catalysis strategy for the synthesis of nitriles from aldehydes and hydroxylamine hydrochloride by using a simple ionic liquid (IL) (e.g., 1-butyl-3-methylimidazolium chloride, [BMIm][Cl]) as a catalyst. It is found that [BMIm][Cl] can tolerate various aliphatic and aromatic aldehydes containing different substituents, including a series of lignin-derived aldehydes, affording the corresponding nitriles in 66–99% yields under metal-/sulfur-/cyano-free conditions at 70 °C. Mechanistic investigations reveal that the acidic protons, polarization, electrostatic effect, hydrogen-bonding interactions, and nucleophilic attack all contribute to the generation of products. This strategy provides a green, simple, and efficient strategy to synthesize nitriles from biomass-derived aldehydes by an evoked multiple-interaction synergetic catalysis process from a simple [BMIm][Cl] ionic liquid catalyst.