Metal-proline complexes of various metals like Zn, Cd, Hg, and Pb were found to be good catalysts for direct Mannich reaction in water medium at room temperature, smoothly affording the β-amino carbonyl compounds in excellent yields. Among the catalyst cadmium-proline complex gave high yield in lesser time. All the catalysts were easily separated from the reaction mixture by water extraction and among this cadmium -proline complex was found to be most stable and can be recycled five times without losing its catalytic activity.
Cd-proline Complex Catalyzed Direct one-Pot three Component Mannich Reaction in Water Medium