Rhodobacter sphaeroide as a new biocatalysts were investigated in the asymmetric reduction of ketones to chiral alcohols. The cells were used in an aqueous system for the asymmetric reduction of acetophenone to prepar...Rhodobacter sphaeroide as a new biocatalysts were investigated in the asymmetric reduction of ketones to chiral alcohols. The cells were used in an aqueous system for the asymmetric reduction of acetophenone to prepare (S)-1-phenyl-ethanol by photo-electron-transfer reactions. It is found that higher product yield and product enantiomeric excess could be achieved. The results show that the enantiomer excess of the chiral alcohols was up to 99%(e.e.) and the yield is more than 90%. The effects of DCMU and the optimal reaction conditions on the reaction were investigated. The results show that the reaction was controlled by light completely, the optimal substrate concentration is 17.0 mmol/L, the optimal cell mass concentration is \{0.2 g/mL,\} the optimal pH is 7—8, the optimal reaction time was 72 h.展开更多
A chiral phosphorous derivatizing agent prepared from PCl3 and (S)-BINOL was described. It is used to determine the enantiomeric excess of chiral alcohols and amines by 31P NMR.
Novel chiral multidentate P3N4-type ligand has been synthesized and characterized by NMR and HRMS.Using i-PrOH as solvent and hydrogen source, asymmetric transfer hydrogenation of various ketones was investigated. The...Novel chiral multidentate P3N4-type ligand has been synthesized and characterized by NMR and HRMS.Using i-PrOH as solvent and hydrogen source, asymmetric transfer hydrogenation of various ketones was investigated. The catalyst generated in situ from chiral multidentate aminophosphine ligand（R,R,R,R）-3 and IrCl（CO）（PPh3）2exhibited highly catalytic activity and excellent enantioselectivity under mild conditions, achieving the corresponding chiral alcohols with up to 99% yield and 99% ee.展开更多
A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new（（Rax）-BuP）/（R,R）-DPEN-Ru（Ⅱ） complex catalyst system.The hydrogenation ...A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new（（Rax）-BuP）/（R,R）-DPEN-Ru（Ⅱ） complex catalyst system.The hydrogenation of 2-methylacetophenone in n-butanol （t-BuOK/Ru =45.6/1,S/C = 500,20 atm.of H2,20℃,48 h） afforded（S）-1-（2＇-methylphenyl）ethanol in 92%ee and〉99% conversion.展开更多
Asymmetric reduction of the heteroaryl prochiral ketones to corresponding chiral alcohols by Daucus carota was studied. The study highlights selective bioreduction of different substituted heteroaryl ketones (1a - 1j)...Asymmetric reduction of the heteroaryl prochiral ketones to corresponding chiral alcohols by Daucus carota was studied. The study highlights selective bioreduction of different substituted heteroaryl ketones (1a - 1j) to their respective chiral alcohols (2a - 2j) using plant dehydrogenase enzymes present in Daucus carota in good yields (60% - 95%) and enantioselectivity (76% - 99%) with S-form configuration. The results obtained confirm that the membrane bound dehydrogenase enzyme has broad substrate specificity and selectivity in catalyzing both six and five membered heteroaryl methyl ketones. The present methodology demonstrates promising and alternative green route in the synthesis secondary chiral alcohols of biologically importance in a simple, inexpensive and eco-friendly process.展开更多
Chiral secondary alcohols with additional functional groups are frequently required as important and valuable synthons for pharmaceuticals, agricultural and other fine chemicals. With the advantages of environmentally...Chiral secondary alcohols with additional functional groups are frequently required as important and valuable synthons for pharmaceuticals, agricultural and other fine chemicals. With the advantages of environmentally benign reaction conditions, broad reaction scope, and high stereoselectivity, biocatalytic reduction of prochiral ketones of- fers significant potential in the synthesis of optically active alcohols. A CmCR homologous carbonyl reductase from Pichia guilliermondii NRRL Y-324 was successfully overexpressed. Substrate profile characterization revealed its broad substrate specificity, covering aryl ketones, aliphatic ketones and ketoesters. Furthermore, a variety of ketone substrates were asymmetrically reduced by the purified enzyme with an additionally NADPH regeneration system. The reduction system exhibited excellent enantioselectivity （~ 99% ee） in the reduction of all the aromatic ketones and ketoesters, except for 2-bromoacetophenone （93.5% ee）. Semi-preparative reduction of six ketones was achieved with high enantioselectivity （〉99% ee） and isolation yields （〉80%） within 12 h. This study provides a useful guidance for further application of this enzyme in the asymmetric synthesis of chiral alcohol enantiomers.展开更多
文摘Rhodobacter sphaeroide as a new biocatalysts were investigated in the asymmetric reduction of ketones to chiral alcohols. The cells were used in an aqueous system for the asymmetric reduction of acetophenone to prepare (S)-1-phenyl-ethanol by photo-electron-transfer reactions. It is found that higher product yield and product enantiomeric excess could be achieved. The results show that the enantiomer excess of the chiral alcohols was up to 99%(e.e.) and the yield is more than 90%. The effects of DCMU and the optimal reaction conditions on the reaction were investigated. The results show that the reaction was controlled by light completely, the optimal substrate concentration is 17.0 mmol/L, the optimal cell mass concentration is \{0.2 g/mL,\} the optimal pH is 7—8, the optimal reaction time was 72 h.
基金We are very grateful for the financial support of the National Natural Science Foundation of China (No.29872016) and the Hong Kong Polytechnic University ASD Fund.
文摘A chiral phosphorous derivatizing agent prepared from PCl3 and (S)-BINOL was described. It is used to determine the enantiomeric excess of chiral alcohols and amines by 31P NMR.
基金the National Natural Science Foundation of China (No. 21173176)the Program for Innovative Research Team in Chinese Universities (No. IRT_14R31)+1 种基金the Fundamental Research Funds for the Central Universities (No. 20720150040)NFFTBS (No. J1310024) for financial support
文摘Novel chiral multidentate P3N4-type ligand has been synthesized and characterized by NMR and HRMS.Using i-PrOH as solvent and hydrogen source, asymmetric transfer hydrogenation of various ketones was investigated. The catalyst generated in situ from chiral multidentate aminophosphine ligand（R,R,R,R）-3 and IrCl（CO）（PPh3）2exhibited highly catalytic activity and excellent enantioselectivity under mild conditions, achieving the corresponding chiral alcohols with up to 99% yield and 99% ee.
基金the National Natural Science Foundation of China(Nos.20343005,20473107,20673130,and 20773147)the Hong Kong PolyU Joint Supervision Scheme(A-PH78) for financial support.
文摘A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new（（Rax）-BuP）/（R,R）-DPEN-Ru（Ⅱ） complex catalyst system.The hydrogenation of 2-methylacetophenone in n-butanol （t-BuOK/Ru =45.6/1,S/C = 500,20 atm.of H2,20℃,48 h） afforded（S）-1-（2＇-methylphenyl）ethanol in 92%ee and〉99% conversion.
文摘Asymmetric reduction of the heteroaryl prochiral ketones to corresponding chiral alcohols by Daucus carota was studied. The study highlights selective bioreduction of different substituted heteroaryl ketones (1a - 1j) to their respective chiral alcohols (2a - 2j) using plant dehydrogenase enzymes present in Daucus carota in good yields (60% - 95%) and enantioselectivity (76% - 99%) with S-form configuration. The results obtained confirm that the membrane bound dehydrogenase enzyme has broad substrate specificity and selectivity in catalyzing both six and five membered heteroaryl methyl ketones. The present methodology demonstrates promising and alternative green route in the synthesis secondary chiral alcohols of biologically importance in a simple, inexpensive and eco-friendly process.
基金This work was financially supported by the National Natural Science Foundation of China （No 21276082）, Ministry of Science and Technology, P. R. China （No.2011CB710800）, China National Special Fund for State Key Laboratory of Bioreactor Engineering （No. 2060204）.
文摘Chiral secondary alcohols with additional functional groups are frequently required as important and valuable synthons for pharmaceuticals, agricultural and other fine chemicals. With the advantages of environmentally benign reaction conditions, broad reaction scope, and high stereoselectivity, biocatalytic reduction of prochiral ketones of- fers significant potential in the synthesis of optically active alcohols. A CmCR homologous carbonyl reductase from Pichia guilliermondii NRRL Y-324 was successfully overexpressed. Substrate profile characterization revealed its broad substrate specificity, covering aryl ketones, aliphatic ketones and ketoesters. Furthermore, a variety of ketone substrates were asymmetrically reduced by the purified enzyme with an additionally NADPH regeneration system. The reduction system exhibited excellent enantioselectivity （~ 99% ee） in the reduction of all the aromatic ketones and ketoesters, except for 2-bromoacetophenone （93.5% ee）. Semi-preparative reduction of six ketones was achieved with high enantioselectivity （〉99% ee） and isolation yields （〉80%） within 12 h. This study provides a useful guidance for further application of this enzyme in the asymmetric synthesis of chiral alcohol enantiomers.
