Preparation and Performance Study of a New Cinchonine-Based Catalyst

Using cinchonine as a raw material, a cinchonine-based isonitrile monomer was prepared after multistep transformation, and finally cinchonine-based catalyst was prepared by polymerization initiated by 4-methoxyphenylethynyl(chloro)bis(triethylphosphine)palladium(II). The new catalyst was used to catalyze asymmetric aldol reactions between cyclohexanone and aromatic aldehydes with different substituent groups. The reaction of cyclohexanone and 3-nitrobenzaldehyde in methanol afforded an enantiomeric excess ( ee ) value of up to 55% and a diastereomeric ratio ( dr ) of up to 30:70, indicating high performance of the catalyst. The synthesized compounds were characterized by HPLC, IR, and 1 H NMR.