Studies On Direct Aldol Reactions Catalyzed By Amino Acid In Green Solvents

The thesis has focused on the study on direct aldol reaction between aldehydes and ketones catalyzed by amino acid in green solvents.In part Ⅰ , the direct aldol reactions catalyzed by lysine in aqueous were studied in detail. The results indicated that water was an effective green solvent for direct aldol reaction catalyzed by lysine. Good yields were obtained when electron-deficient aromatic aldehydes reacted with ketones catalyzed by 30mol% lysine in water, added 20mol% anionic surfactant, sodium dodecyl sulfate (SDS). The higher yields and the shorter reaction time in lysine catalyzing reactions were than those of the corresponding reactions in proline catalyzing, implying that lysine had a greater catalytic reactivity in water compared to proline. The reaction may proceed in micelle with an enamine mechanism that is similar to the Aldolase catalysis.In part Ⅱ, the asymmetric direct aldol reactions catalyzed by prolinein the green media——TX-100 were studied in detail. The resultsindicated that high chemical yield (95%), high diastereoselectivity (1/99) and good enantioselectivity (92% ee) were obtained when alicyclic ketones reacted with electron-deficient aromatic aldehydes catalyzed by proline (10mol%) in TX-100. The electron-efficient aromatic aldehydes showed sluggish reactions and gave moderate yields. The aliphatic ketones also gave high yields but no enantioselectivity. Proline catalysis reactions exhibit higher activity and broader substrates in TX-100 compared to other solvents. Tx-100 is a good green media for small organo-molecular catalysis reactions.