The Preparation Of Hairy Nanoparticles Grafted With Proline Polymer Chains On Surface Of Nanoparticles And Its Application In Asymmetric Aldol Reaction

The supported catalyst has received much attention, its advantages is high stability, extensivesuitability to solvents, easy separation and purification of product, lower environmental hazard, easyseparation recovery from reaction system and reuse, and so on. In this thesis, a new hairy silicananoparticles linking Poly(O-methyl acroloyl-L-hyp) chains had been synthesized by reversible additionfragmentation chain transfer (RAFT). And the catalyst had been used in asymmetric direct alodl reaction toinvestigate the optimized reaction condition.The paper could be divided into two parts.Synthesis and characterization of hairy silica nanoparticles grafted with Poly(O-methylacroloyl-L-hyp)：O-methyl acroloyl-L-hyp hydrochloride was prepared by the reaction of L-hyp and methylcarbonyl chloride in the trifluoro acetic acid. Then polymerizable monomer N-substituted Boc–O-methylacroloyl-L–hyp was obtained from the N-boc protection of O-methyl acroloyl-L-hyp hydrochlorid. RAFTchain revesible agent was attached on the surface of silica nanoparticles, and hairy silica nanoparticleslinking polymeric chains with N-Boc-hyp were obtained from surface of silica by reversible additionfragmentation active radical polymerization (RAFT) technical. Finally hairy silica nanoparticles graftedpoly(O-methyl acroloyl-L-hyp) chains were achieved by deprotection of catalyst obtained in the previousstep. The chemical compounds and catalyst were characterized by nuclear magnetic resonance (NMR), IRspectra and DG-DTG.Hairy silica nanoparticles grafted with Poly(O-methyl acroloyl-L-hyp) was carried out inasymmetric direct aldol reaction, and the performance of the catalyst were benchmarked in typical aldolreaction of p-nitrobenzaldehyde with acetone. The experiment results show that this catalyst in asymmetricaldol reaction of p-nitrobenzaldehyde with acetone perform better catalytic activity and enantioselectivity(47%yield and66.6%ee value) in optimized reaction conditions(DMF as solvent,10mol%catalyticamount and in0℃). Through simple separation, catalyst can be duplicated.