Synthesis Of Polyacrylonitrile Polymers-Supported 9-Amino Cinchona Alkaloids Catalysts And Their Applications In The Asymmetric Reaction

Cinchona alkaloids had been researched and attracted people's attention for decades. Due to its rigid frame and active sites, it was widely applied in asymmetric catalytic reactions with excellent catalytic properties. In 1995, Henri Brunner introduced amino-group instead of hydroxyl group in C9 of cinchona alkaloids, and opened the door of research 9-amino cinchona alkaloids derivatives in asymmetric catalytic reactions.In this thesis, the low-cost and facile cinchonidine as the raw material,9-hydroxyl group was substituted by 9-amino group with simultaneous Walden inversion to give 9-amino cinchona alkaloid 1. Polyacrylonitrile polymer-supported cinchona alkaloid primaryamine cataysts 2a-d were prepared by reaction of the obtained 9-amino cinchona alkaloid 1 with acrylonitrile in different molar ratioes for the first time.The structures and surface morphologies of polymer catalysts 2a-d had been characterized by NMR, FT-IR, TG, XPRD, N2 adsorption-desorption isothermal curve, TEM and SEM.The synthesized catalysts 2a-d were applied in the asymmetric Aldol reaction of p-nitroben-zaldehyde with cyclohexanone, and the optimum experimental conditions were screened in details. The product 5a in 95.8% yield,96.4% ee and 90/10 dr was obtained at 25℃for 96 h in 2 mL water and 7.5 mol% catalyst 2a. After the reaction was completed, the catalyst 2a could be recovered by filtration and reused in the asymmetric Aldol reaction. However, yield, ee and dr were reduced sharply after fourth recycled times.