Synthesis Of Chiral Guanidines And Their Application In Asymmetric Aldol Reaction And Henry Reactions

Research on synthesis of chiral catalysts, and their application in asymmetriccatalysts is a very important field of organic chemistry. In this field, small organicmolecules are one of representative catalysts systems. In small organic moleculecatalysts, proline derivatives are the most common kind of chiral catalysts. Someadvantages, such as inexpensive reactive substrates, simple synthetic process and highcatalytic activity make proline derivatives be concerned.Guanidines are one of important organic compounds, because of their strongbasicity, have been used in catalytic fields. On the base of our previous work onsynthesis and application of guanidine derivatives, we design and synthesize a seriesof basic chiral guanidines containing proline chiral skeleton, and subsequentlyevaluate their asymmetric catalytic activity in Aldol and Henry reaction, in order todesign and synthesis of highly effective chiral guanidine catalysts.In this thesis, we synthesized two kinds of chiral guanidines a-h, by introducingprolylhydrazine and prolinamide into the structure of guanidine respectively. Chiralguanidines a-h were characterized by1HNMR,13CNMR and HRMS. In asymmetricAldol reactions, chiral guanidine d exhibited better catalytic activity than other chiralguanidines a-h. When5mol%of d and4equive of cyclohexanone were used,corresponding.product was obtained in up to81%yield and up to99%ee. However,chiral guanidine derivatives a-h showed low catalytic activity in Henry reaction, andthe corresponding product was obtained in85%yield and33%ee. Relativeoptimization of reaction conditions is underway.