Task-specific acidic ionic liquid [CmMIm]Cl-catalyzed one-pot multicomponent synthesis of β-aminocarbonyl compounds at room temperature

Abstract

Sustainable catalytic systems that promote multicomponent reactions under mild and environmentally benign conditions are highly desirable in modern organic synthesis. Herein, we report a task-specific ionic liquid, 3-(carboxymethyl)-1-methyl-3-1H-imidazole-3-ium chloride ([CmMIm]Cl), as a dual-functional catalyst and reaction medium for the one-pot synthesis of β-aminocarbonyl compounds via the Mannich reaction. The protocol proceeds efficiently at ambient temperature, affording excellent yields of products within short reaction times. Notably, the method avoids toxic metal catalysts, reduces solvent consumption, and enables straightforward product isolation. Mechanistic insights suggest that cooperative activation arising from the acidic (–COOH) and basic (imidazolium nitrogen) sites of the ionic liquid facilitates rapid imine formation and subsequent C–C bond formation with broad substrate scope. Furthermore, [CmMIm]Cl can be easily recovered and reused for successive cycles without significant loss of activity, highlighting its stability and practical applicability. Overall, this study demonstrates that [CmMIm]Cl represents an efficient and sustainable platform for C–C and C–N bond formation through Mannich-type multicomponent reactions under mild and green conditions.