Synthesis of new ionic-liquid-tagged organocatalysts and their application in stereoselective direct aldol reactions

New amino acid—1,2,3-triazolium conjugates were synthesized by establishing a 1,2,3-triazolium unit to the amino acid through Cu-catalyzed alkyne-azide cycloaddition and subsequent N-methylation. These products were applied as ionic-liquid-tagged organocatalysts in asymmetric direct aldol reactions. Remarkably, a lysine-derived conjugate performed better than proline derivatives. Evidence was found that IL-tagging improved the catalytic performance. Recycling of the organocatalyst was easily possible by extraction of products.