Fullerene-proline hybrids: Synthesis, characterization and organocatalytic properties in aldol reactions

摘要

Two novel C_(60)-proline hybrids 1 and 2 were synthesized in which the active proline unit is located either in close proximity to C_(60) or away from the fullerene sphere. The synthesis of 1 and 2 was achieved by condensation reactions of the fulleropyrrolidines formed upon the 1,3-dipolar cycloaddition reaction of in-situ generated azomethineylides onto C_(60) with proline derivatives. The catalytic activity of 1 and 2 in typical aldol reactions between acetone or cyclohexanone and 2- or 4-nitrobenzaldehyde in terms of yield and enantioselectivity was evaluated. The effect of solvent, the organocatalyst loading as well as the amount of base added were examined.