Diastereoselective three-component Mannich reaction catalyzed by prolinated MWCNTs

Asymmetric Mannich and Mannich-type reactions are important carbon-carbon bond-forming reactions that provide access to enantiomerically enriched β-amino carbonyl derivatives.[1] These compounds are useful precursors for synthesis of β- lactams, α and ᵞ-aminoalcohols, α and β-amino acid derivatives, peroxy acetylenic alcohols/ethers, and medicinally important materials. Several strategies[2,3] are available for diastereoselective synthesis of β-amino carbonyl compounds, including organocatalysis transition-metal catalysis, Bronsted and Lewis acid catalysis, phasetransfer catalysis, biocatalysis and ionic-liquid catalysis. Herein we report a highly anti-diastereoselective three-component Mannich reaction of aromatic amines and aldehydes with cyclohexanone in water as solvent and efficient nano organocatalyst. Reusability, easy workup, inexpensive, ready availability, short reaction time and its high diastereoselctivity 70-100% makes this catalyst an attractive alternative to the existing catalysts for the synthesis of β-amino carbonyls.