Synthesis Of PVC Supported L-proline Derivative And Its Catalytic Properties For Direct Asymmetric Aldol Reaction

Study on the small organic molecule catalyzed asymmetric reactions has been developed into a new field in recent years. It overcomes the shortcomings of enzyme catalyst and Transition metal catalyst. With the development of the small organic molecule catalyzed asymmetric reactions, the traditional small organic molecule catalysts have exposed some problems. For example, the amount of catalyst is large; reuse of catalyst is not easy; Organic solvent used as reaction media pollutes environment. For overcoming these problems, polymer supported catalysts have been attracted more attention. In this paper, we have synthesized two functionalized polymers with amino groups using PVC, and the proline will be grafted on the polymers. We optimize the reaction conditions, explore the scope of the reactions and reused the catalysts. The work could be divided into three parts.(1) Industrial polyvinyl chloride was modified via graft reaction, condensation reaction, with tetraethylene penamine to form a dark brown polymer support catalyst (PTP). It has been characterized by IR etc.(2) The asymmetric Aldol reaction has been catalized by PTP.It can be seen from optimization of reaction conditions that PTP has high catalyst activity and selectivity(yield up to 94%,ee up to 97%) in addition of base in water. Under the best condition, substrate generality has been examined. In these substrates, the aldehydes with electron attracting group are better than with electron donor group. Recycling studies of catalysts in addition of base in water has been carried. PTP can be reused for 15 times without lost of catalyst activity.(3) Industrial polyvinyl chloride was modified via hydrolytic reaction, graft reaction, condensation reaction, with tetraethylene penamine to form a dark brown polymer support catalyst(HPTP).The catalyst has been catalized the asymmetric Aldol reaction. It can be seen that hydrophilic PVC-TEPA-Pro has high catalyst activity, but normal selectivity in water; On the country, in organic solvents, the polymer supported catalyst has better selectivity, but low activity. Substrate generality has been examined. In these substrates, the aldehydes with electron attracting group are better than with electron donor group. The catalyst can be reused.