The direct asymmetric aldol reaction between various aldehydes and acetone catalyzed by L-proline catalyst was successfully carried out in supercritical CO_(2) (scCO_(2)) and 1,1,1,2-tetrafluoroethane (R-134a) fluids....The direct asymmetric aldol reaction between various aldehydes and acetone catalyzed by L-proline catalyst was successfully carried out in supercritical CO_(2) (scCO_(2)) and 1,1,1,2-tetrafluoroethane (R-134a) fluids.The enantioselectivity of 84% ee to the targeted product was achieved under 20 MPa,40 °C,and 15 mol% of the catalyst in supercritical CO_(2) (scCO_(2)) fluid.The effects of reaction parameters,such as temperature,pressure,catalyst loading and different substituted aldehydes on both enantioselectivity and aldol yield were discussed.The titled reaction was also performed in 1,1,1,2-tetrafluoroethane,and the obtained results were compared with those in scCO2.This new reaction procedure provides an environmental asymmetric aldol reaction system as compared with that in organic solvents.展开更多
基金the National Natural Science Foundation of China (20976102)Specialized Research Fund for the Doctoral Program of Higher Education (20070718003)
文摘The direct asymmetric aldol reaction between various aldehydes and acetone catalyzed by L-proline catalyst was successfully carried out in supercritical CO_(2) (scCO_(2)) and 1,1,1,2-tetrafluoroethane (R-134a) fluids.The enantioselectivity of 84% ee to the targeted product was achieved under 20 MPa,40 °C,and 15 mol% of the catalyst in supercritical CO_(2) (scCO_(2)) fluid.The effects of reaction parameters,such as temperature,pressure,catalyst loading and different substituted aldehydes on both enantioselectivity and aldol yield were discussed.The titled reaction was also performed in 1,1,1,2-tetrafluoroethane,and the obtained results were compared with those in scCO2.This new reaction procedure provides an environmental asymmetric aldol reaction system as compared with that in organic solvents.
