In this thesis, the direct aldol reactions between aldehydes and ketones catalyzed by histidine and dipeptide in green media have been studied in detail.In partâ… , the direct aldol reactions catalyzed by histidine in PEG-200 were studied. The results indicated that high chemical yield (96%), high diastereoselectivity (anti/syn=1/99) and good enantioselectivity (88% ee) were obtained when alicyclic ketones reacted with electron-deficient aromatic aldehydes catalyzed by histidine (30mol%) in PEG-200 or PEG-300. Thus,PEG-200 and PEG-300 are good green medium for small organo-molecular catalysis reactions.In partâ…¡, the asymmetric direct aldol reactions catalyzed by dipeptide(H-Pro-His-OH) under solvent-free condions were studied in detail. The results indicated that the dipeptide could catalyze the direct aldol reactions between electron-deficient aromatic aldehydes and ketones effectively with small load (2mol%-5mol%). The addition of small amount of water could accelerate the reactions and improve the enantioselectivity of the reactions.
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