ovel chiral β-amino alcohols containing sulfide or sulfonyl groups were synthesized from (R)-cysteine. Their chiral induction in the asymmetric borane reduction of prochiral ketones was investigated. Optically acti...ovel chiral β-amino alcohols containing sulfide or sulfonyl groups were synthesized from (R)-cysteine. Their chiral induction in the asymmetric borane reduction of prochiral ketones was investigated. Optically active secondary alcohols with moderate or high e. e. values were obtained, and the causes of different enantioselectivities between these two sulfur-containing chiral β-amino alcohols were researched.展开更多
Chiral oxazoborolidine borane complex was prepared from (αs, 4s)-2-dichloromethyl-4, 5-dihydro-α-(4-nitrophenyl)-4-oxazolemethanol with Borane in THF. The borane modified by chiral oxazoborolidine enantioselectively...Chiral oxazoborolidine borane complex was prepared from (αs, 4s)-2-dichloromethyl-4, 5-dihydro-α-(4-nitrophenyl)-4-oxazolemethanol with Borane in THF. The borane modified by chiral oxazoborolidine enantioselectively reduced aromatic ketones to second-alcohol with about 95%yield and medium optical yields. In the end of article, results are discussed and reduction mechanism is shown which proves the resulting major isomers fit very well.展开更多
A series of novel bis-squaramidoacid ligands were prepared. Prochiral ketone and diketones were direct reduced by borane in the presence of these ligands giving secondary alcohol products with enantiomeric excesses u...A series of novel bis-squaramidoacid ligands were prepared. Prochiral ketone and diketones were direct reduced by borane in the presence of these ligands giving secondary alcohol products with enantiomeric excesses up to 64.2% for w-bromoacetophenone and 90.0% for 1, 6-diphenyl-1, 6-hexanedione.展开更多
The asymmetric borane reduction of carbonyl compounds using chiral catalysts is one of the most active research. Among them,Oxazaborolidines developed by Corey are most significant- Herein. we report the use of sufony...The asymmetric borane reduction of carbonyl compounds using chiral catalysts is one of the most active research. Among them,Oxazaborolidines developed by Corey are most significant- Herein. we report the use of sufonylamides as chiral catalysts to reduce aromatic ketone in high yield and with e.e. of up to 91 %. Scheme:展开更多
Asymmetric reduction of ct-hydroxy aromatic ketones was carded out by using carrot enzymes system, yielding corresponding chiral vicinal diols with special functional groups. The optimum reaction conditions were obtai...Asymmetric reduction of ct-hydroxy aromatic ketones was carded out by using carrot enzymes system, yielding corresponding chiral vicinal diols with special functional groups. The optimum reaction conditions were obtained after investigation of various influencing factors. Chiral aryl vicinal diols were produced with good yields and excellent enantiomeric excesses under appropriate conditions. Meanwhile, the steric factors and electronic effects of the substituents on the aromatic ring were shown to have an interesting influence on both yield and enantioselectivity.展开更多
The influence of asymmetric reduction rolling (ARR) on the microstructure, texture and mechanical properties of AZ91 was investigated. The microstructural characteristics of the AZ91 sheet processed by symmetric ro...The influence of asymmetric reduction rolling (ARR) on the microstructure, texture and mechanical properties of AZ91 was investigated. The microstructural characteristics of the AZ91 sheet processed by symmetric roiling (SR) were the twins, intersection of twins and dynamic recrystalization (DRX) grains around the coarse grains and within the twins. However, the amount of twins and DRX grains in ARRed AZ91 was much smaller than that in SRed AZ91. The SRed AZ91 after annealing exhibited fine DRX grains and some coarse grains with a size of ~ 100 pro. The grains in ARRed AZ91 after annealing were much finer and more homogeneous than those in SRed AZ91 after annealing. The intensity of basal texture of ARRed AZ91 after annealing was lower than that of SRed AZ91 rolling after annealing. The average Schmid factor of ARRed AZ91 is 0.34, which is higher than that of SRed AZ91. The yield strength and ultimate tensile strength of the ARRed AZ91 sheet were inCreased to 16.1% and 31.8% compared to SRed AZ91 sheet, from 155 to 180 MPa, and from 220 to 290 MPa, respectively. The improvement of mechanical properties in ARRed AZ91 after annealing was attributed to much finer, more homogeneous DRX grains and weaker basal texture.展开更多
Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce(S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueou...Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce(S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueous-organic solvent biphasic system.The possible influential factors were examined thoroughly according to their effects on conversion rate and e.e of the product.Organic solvents were rated by their biocompatibility and conversion potential.The immobilized cells [125 mg/mL in 20 mmol/L Tris-HCl buffer and 5%(j) octane at pH 8] showed the best conversion with a substrate concentration of 1.42 g/L at 30℃ with glucose as co-substrate for cofactor regeneration.Sequential 8-batch process was carried out with immobilized cells with a slow decrease in conversion and e.e.The immobilized cells showed stable catalytic activity with 50% reserved activity and are superior especially in reusability in comparison with resting cells.展开更多
Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae)...Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae) as a whole-cell biocatalyst.However,some of the enzymes catalyzing these reactions in S.cerevisiae are still unknown up to date.In this report,two carbonyl reductases,OdCRl and OdCR2,were successfully discovered,and cloned from S.cerevisiae using a genome-mining approach,and overexpressed in Escherichia coli(E.coli).Compared with OdCR1,OdCR2 can reduce 4-oxodecanoic acid and 5-oxodecanoic acid asymmetrically with higher stereoselectivity,generating(R)-γ-decalactone(99% ee) and(R)-δ-decalactone(98% ee) in 85% and 92%yields,respectively.This is the first report of native enzymes from S.cerevisiae for the enzymatic synthesis of chiral γ-and δ-lactones which is of wide uses in food and cosmetic industries.展开更多
Two remarkable reducing agents NaBH4 (or NaBD4)/SnCl2(or SnCl4·2Et2O) with chiral ligands are applied to the asymmetric reduction of carbonyl compounds with excellent chemical yields and enantioselective excesses.
The favorable microbes for the asymmetric reduction of prochiral aromatic ketones was isolated from soil using acetophenone as the sole carbon source,when the asymmetric reduction of acetophenone(ACP)to chiral a-phene...The favorable microbes for the asymmetric reduction of prochiral aromatic ketones was isolated from soil using acetophenone as the sole carbon source,when the asymmetric reduction of acetophenone(ACP)to chiral a-phenethyl alcohol(PEA)was chosen as the model reaction.Two microbe strains with excellent catalytic activity were obtained.They were Geotrichum candidum and Pichia pastoris identified by bacteria identification.The product of the asymmetric reduction of ACP catalyzed by Pichia pastoris was mainly R-PEA and that by Geotrichum candidum was mainly S-PEA.The yield and enantiomeric excesses(e.e.)could respectively reach 75%and 90%for Pichia pastoris,and 80%and 70%for Geotrichum candidum,much higher than those catalyzed by baker’s yeast.展开更多
Asymmetric reduction of acetophenone O methyloxime with reagents in situ prepared from L proline and borane has been investigated. A series of conditions optimization were made, including an examination ...Asymmetric reduction of acetophenone O methyloxime with reagents in situ prepared from L proline and borane has been investigated. A series of conditions optimization were made, including an examination of the effect of the temperature of catalyst pretreatment, the temperature of reduction, the amount of borane, the additive, the solvent, the reducing agent and various chiral auxiliaries on the enantioselectivity. Under the optimal condition, ( S ) α phenylethylamine was obtained in 53% yield with 83 1% ee in the presence of 25 mol% L proline.展开更多
Asymmetric reduction of diketones with borane reagents generated in situ using cheap and available NaBH4 and SnCl2 in the presence of (S)-(-)-α,a-diphenyl-2-pyrrolidinemethanol was successfully achieved to yield ...Asymmetric reduction of diketones with borane reagents generated in situ using cheap and available NaBH4 and SnCl2 in the presence of (S)-(-)-α,a-diphenyl-2-pyrrolidinemethanol was successfully achieved to yield the corresponding chiral diols with excellent stereoselectivity and enantioselectivity. And the chiral diol was transformed into optically pure C2-symmetricl chiral amine or thioether.展开更多
The recent methods of resolution, enantiomeric excess determination and synthesis of optically active alcohols from asymmetric reduction of prochiral ketones are reviewed in the article with references. Important func...The recent methods of resolution, enantiomeric excess determination and synthesis of optically active alcohols from asymmetric reduction of prochiral ketones are reviewed in the article with references. Important functions and applications of optically active alcohols in biological and chemical research area are described in an introduction part. The following part deals with resolution and enantiomeric excess determination of racemic alcohols. The next part discusses asymmetric reduction of prochiral ketone and related compounds, which including: (a) Reduction by chirally modified aluminum and boron hydrides; (b) Catalytic reduction with chiral transition metal complexes; (c) Enantioselective reduction by hydride transfer from carbon; (d) Biocatalytic reduction; (e) Asymmetric synthesis of chiral nonracemic alcohols with help of physical methods. A conclusion about optically active alcohols from asymmetric reduction of ketones followes in the final part of article.展开更多
A concise method was developed to prepare chiral a-monofluorinated-β-amino esters through N-sulfinyl urea catalyzed asymmetric hydrosilylation of a-fluoro-β-enamino esters, which affords high yields, good to high di...A concise method was developed to prepare chiral a-monofluorinated-β-amino esters through N-sulfinyl urea catalyzed asymmetric hydrosilylation of a-fluoro-β-enamino esters, which affords high yields, good to high di- astereoselectivities (up to〉99/1), and moderate to good enantioselectivities (up to 83% ee).展开更多
Direct enantioselective reduction of the C=C bond ofβ-polyfluoro-alkylated enones is an important but long-pending subject in asymmetric catalysis.Here,we report on the viability of visible light-driven cooperative p...Direct enantioselective reduction of the C=C bond ofβ-polyfluoro-alkylated enones is an important but long-pending subject in asymmetric catalysis.Here,we report on the viability of visible light-driven cooperative photoredox and chiral hydrogenbonding catalysis to effectively address this challenge,as a variety of products are obtained in high yields(up to 85%)with good to excellent enantioselectivities(up to 98%ee).The formation of thermodynamically favorable enol intermediates after double single-electron reduction represents the center of the success.Additionally,the utility of the current method is validated by the convenient regio-specific and-diverse synthesis of various deuterated derivatives for these products using inexpensive D_(2)O as the deuterium source.展开更多
(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1...(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1 that efficiently transforms 4-hydroxy-2-butanone to(R)-1,3-butanediol was isolated from soil samples. Based on morphological, physiological, and biochemical tests and 5.8 S-internal transcribed spacer sequencing, the strain was identified as Pichia kudriavzevii QC-1. The reaction conditions were optimized to 35 ℃, pH 8.0, rotation speed 200 rpm, and 6:5 mass ratio of glucose to 4-hydroxy-2-butanone. Evaluation of the effects of 4-hydroxy-2-butanone concentrations on yield and cell survival rate showed that 85.60 g·L^-1 product accumulated, with an enantiomeric excess of more than 99%, when 30 g·L^-14-hydroxy-2-butanone was added at 0, 10, and 30 h in a 3-L bioreactor. Thus, strain QC-1 showed excellent catalytic activity and stereoselectivity for the synthesis of(R)-1,3-butanediol from 4-hydroxy-2-butanone.展开更多
The reduction reagents prepared from sodium borohydride, I-2 and a catalytic amount of chiral ferrocenyl amino alcohols 2a-e have been successfully applied to the enantioselective reduction of ketones. The optically a...The reduction reagents prepared from sodium borohydride, I-2 and a catalytic amount of chiral ferrocenyl amino alcohols 2a-e have been successfully applied to the enantioselective reduction of ketones. The optically active secondary alcohols were obtained in moderate enantiomeric excess and high chemical yield.展开更多
A series of novel N-squaramidoacid ligands were prepared conveniently. Without converting to corresponding amino alcohols, these ligands could be used in asymmetric borane reduction of prochiral aromatic ketones to gi...A series of novel N-squaramidoacid ligands were prepared conveniently. Without converting to corresponding amino alcohols, these ligands could be used in asymmetric borane reduction of prochiral aromatic ketones to give secondary alcohols in good to excellent enantiomeric excesses. The results showed that N-squaramidoacids are more efficient ligands than N-sulfonyl amino acids. N-Squaryl proline was proved to be an excellent ligand in this catalytic asymmetric process.展开更多
Two new type of 1,3,2-oxazaborolidines were prepared from (Is,2s)-2-amino-1-(4-nitrophenyl)-propane-1-3-diol and were used as catalyst in the asymmetric reduction of acetophenone. The influence of the reaction tempera...Two new type of 1,3,2-oxazaborolidines were prepared from (Is,2s)-2-amino-1-(4-nitrophenyl)-propane-1-3-diol and were used as catalyst in the asymmetric reduction of acetophenone. The influence of the reaction temperature as well as the effect of the structure of catalyst on the enantioselectivity was investigated. The origin of the products' configuration was discussed.展开更多
Easily available D-(+)-camphor-derived chiral mercapto-alcohols 2 and 3 were employed for catalytic asymmetric borane reduction of aromatic ketones. Moderate enantioselectivities with e.e. 20.2–72.1% were obtained wi...Easily available D-(+)-camphor-derived chiral mercapto-alcohols 2 and 3 were employed for catalytic asymmetric borane reduction of aromatic ketones. Moderate enantioselectivities with e.e. 20.2–72.1% were obtained with 10 mol% catalyst. Opposite asymmetric induction was achieved' when mercapto-alcohols 2 and 3 were used.展开更多
文摘ovel chiral β-amino alcohols containing sulfide or sulfonyl groups were synthesized from (R)-cysteine. Their chiral induction in the asymmetric borane reduction of prochiral ketones was investigated. Optically active secondary alcohols with moderate or high e. e. values were obtained, and the causes of different enantioselectivities between these two sulfur-containing chiral β-amino alcohols were researched.
文摘Chiral oxazoborolidine borane complex was prepared from (αs, 4s)-2-dichloromethyl-4, 5-dihydro-α-(4-nitrophenyl)-4-oxazolemethanol with Borane in THF. The borane modified by chiral oxazoborolidine enantioselectively reduced aromatic ketones to second-alcohol with about 95%yield and medium optical yields. In the end of article, results are discussed and reduction mechanism is shown which proves the resulting major isomers fit very well.
文摘A series of novel bis-squaramidoacid ligands were prepared. Prochiral ketone and diketones were direct reduced by borane in the presence of these ligands giving secondary alcohol products with enantiomeric excesses up to 64.2% for w-bromoacetophenone and 90.0% for 1, 6-diphenyl-1, 6-hexanedione.
文摘The asymmetric borane reduction of carbonyl compounds using chiral catalysts is one of the most active research. Among them,Oxazaborolidines developed by Corey are most significant- Herein. we report the use of sufonylamides as chiral catalysts to reduce aromatic ketone in high yield and with e.e. of up to 91 %. Scheme:
基金supported by the National Natural Science Foundation of China(No.21176203)the National Special Fund for State Key Laboratory of Bioreactor Engineering(No.2060204)the Fundamental Research Funds for the Central Universities(No.JUSRP211A12)
文摘Asymmetric reduction of ct-hydroxy aromatic ketones was carded out by using carrot enzymes system, yielding corresponding chiral vicinal diols with special functional groups. The optimum reaction conditions were obtained after investigation of various influencing factors. Chiral aryl vicinal diols were produced with good yields and excellent enantiomeric excesses under appropriate conditions. Meanwhile, the steric factors and electronic effects of the substituents on the aromatic ring were shown to have an interesting influence on both yield and enantioselectivity.
基金financially supported by the National Natural Science Foundation of China(No.51271046)
文摘The influence of asymmetric reduction rolling (ARR) on the microstructure, texture and mechanical properties of AZ91 was investigated. The microstructural characteristics of the AZ91 sheet processed by symmetric roiling (SR) were the twins, intersection of twins and dynamic recrystalization (DRX) grains around the coarse grains and within the twins. However, the amount of twins and DRX grains in ARRed AZ91 was much smaller than that in SRed AZ91. The SRed AZ91 after annealing exhibited fine DRX grains and some coarse grains with a size of ~ 100 pro. The grains in ARRed AZ91 after annealing were much finer and more homogeneous than those in SRed AZ91 after annealing. The intensity of basal texture of ARRed AZ91 after annealing was lower than that of SRed AZ91 rolling after annealing. The average Schmid factor of ARRed AZ91 is 0.34, which is higher than that of SRed AZ91. The yield strength and ultimate tensile strength of the ARRed AZ91 sheet were inCreased to 16.1% and 31.8% compared to SRed AZ91 sheet, from 155 to 180 MPa, and from 220 to 290 MPa, respectively. The improvement of mechanical properties in ARRed AZ91 after annealing was attributed to much finer, more homogeneous DRX grains and weaker basal texture.
文摘Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce(S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueous-organic solvent biphasic system.The possible influential factors were examined thoroughly according to their effects on conversion rate and e.e of the product.Organic solvents were rated by their biocompatibility and conversion potential.The immobilized cells [125 mg/mL in 20 mmol/L Tris-HCl buffer and 5%(j) octane at pH 8] showed the best conversion with a substrate concentration of 1.42 g/L at 30℃ with glucose as co-substrate for cofactor regeneration.Sequential 8-batch process was carried out with immobilized cells with a slow decrease in conversion and e.e.The immobilized cells showed stable catalytic activity with 50% reserved activity and are superior especially in reusability in comparison with resting cells.
基金financially sponsored by the National Key Research and Development Program of China (2016YFA0204300, 2019YFA09005000)the National Natural Science Foundation of China (21536004, 21776085, 21871085)+2 种基金the Natural Science Foundation of Shanghai (18ZR1409900)Key Project of the Shanghai Science and Technology Committee (18DZ1112703)the Fundamental Research Funds for the Central Universities (WF1714026)。
文摘Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae) as a whole-cell biocatalyst.However,some of the enzymes catalyzing these reactions in S.cerevisiae are still unknown up to date.In this report,two carbonyl reductases,OdCRl and OdCR2,were successfully discovered,and cloned from S.cerevisiae using a genome-mining approach,and overexpressed in Escherichia coli(E.coli).Compared with OdCR1,OdCR2 can reduce 4-oxodecanoic acid and 5-oxodecanoic acid asymmetrically with higher stereoselectivity,generating(R)-γ-decalactone(99% ee) and(R)-δ-decalactone(98% ee) in 85% and 92%yields,respectively.This is the first report of native enzymes from S.cerevisiae for the enzymatic synthesis of chiral γ-and δ-lactones which is of wide uses in food and cosmetic industries.
基金Project supported by the Major State Basic Research Development Program(No.G2000048007),the National Natural Science Foundation of China(No.D20032010)and Shanghai Natural Science Council.
文摘Two remarkable reducing agents NaBH4 (or NaBD4)/SnCl2(or SnCl4·2Et2O) with chiral ligands are applied to the asymmetric reduction of carbonyl compounds with excellent chemical yields and enantioselective excesses.
基金This work was supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20050335131)Wuhan Youth Scientist Dawn Foundation(200750731288)Natural Science Foundation of Wuhan University of Science and Technology(2005XY15).
文摘The favorable microbes for the asymmetric reduction of prochiral aromatic ketones was isolated from soil using acetophenone as the sole carbon source,when the asymmetric reduction of acetophenone(ACP)to chiral a-phenethyl alcohol(PEA)was chosen as the model reaction.Two microbe strains with excellent catalytic activity were obtained.They were Geotrichum candidum and Pichia pastoris identified by bacteria identification.The product of the asymmetric reduction of ACP catalyzed by Pichia pastoris was mainly R-PEA and that by Geotrichum candidum was mainly S-PEA.The yield and enantiomeric excesses(e.e.)could respectively reach 75%and 90%for Pichia pastoris,and 80%and 70%for Geotrichum candidum,much higher than those catalyzed by baker’s yeast.
文摘Asymmetric reduction of acetophenone O methyloxime with reagents in situ prepared from L proline and borane has been investigated. A series of conditions optimization were made, including an examination of the effect of the temperature of catalyst pretreatment, the temperature of reduction, the amount of borane, the additive, the solvent, the reducing agent and various chiral auxiliaries on the enantioselectivity. Under the optimal condition, ( S ) α phenylethylamine was obtained in 53% yield with 83 1% ee in the presence of 25 mol% L proline.
基金Project supported by the National Natural Science Foundation of China (Nos. 20525208, 20532040, 20390050).
文摘Asymmetric reduction of diketones with borane reagents generated in situ using cheap and available NaBH4 and SnCl2 in the presence of (S)-(-)-α,a-diphenyl-2-pyrrolidinemethanol was successfully achieved to yield the corresponding chiral diols with excellent stereoselectivity and enantioselectivity. And the chiral diol was transformed into optically pure C2-symmetricl chiral amine or thioether.
文摘The recent methods of resolution, enantiomeric excess determination and synthesis of optically active alcohols from asymmetric reduction of prochiral ketones are reviewed in the article with references. Important functions and applications of optically active alcohols in biological and chemical research area are described in an introduction part. The following part deals with resolution and enantiomeric excess determination of racemic alcohols. The next part discusses asymmetric reduction of prochiral ketone and related compounds, which including: (a) Reduction by chirally modified aluminum and boron hydrides; (b) Catalytic reduction with chiral transition metal complexes; (c) Enantioselective reduction by hydride transfer from carbon; (d) Biocatalytic reduction; (e) Asymmetric synthesis of chiral nonracemic alcohols with help of physical methods. A conclusion about optically active alcohols from asymmetric reduction of ketones followes in the final part of article.
基金Acknowledgement We are grateful for financial supports from the Na- tional Natural Science Foundation of China (Project Nos. 20972151, 21272227 and 91013006).
文摘A concise method was developed to prepare chiral a-monofluorinated-β-amino esters through N-sulfinyl urea catalyzed asymmetric hydrosilylation of a-fluoro-β-enamino esters, which affords high yields, good to high di- astereoselectivities (up to〉99/1), and moderate to good enantioselectivities (up to 83% ee).
基金supported by the National Natural Science Foundation of China(22171072,21925103,22301061)Henan Normal University。
文摘Direct enantioselective reduction of the C=C bond ofβ-polyfluoro-alkylated enones is an important but long-pending subject in asymmetric catalysis.Here,we report on the viability of visible light-driven cooperative photoredox and chiral hydrogenbonding catalysis to effectively address this challenge,as a variety of products are obtained in high yields(up to 85%)with good to excellent enantioselectivities(up to 98%ee).The formation of thermodynamically favorable enol intermediates after double single-electron reduction represents the center of the success.Additionally,the utility of the current method is validated by the convenient regio-specific and-diverse synthesis of various deuterated derivatives for these products using inexpensive D_(2)O as the deuterium source.
基金Financial supports from the National Key R&D Program of China(2018YFC1604100)the National Natural Science Foundation of China(NSFC)[21676120,31872891]+8 种基金the 111 Project[111-2-06]the Highend Foreign Experts Recruitment Program[G20190010083]the Program for Advanced Talents within Six Industries of Jiangsu Province[2015-NY007]the National Program for Support of Top-notch Young Professionalsthe Fundamental Research Funds for the Central Universities[JUSRP51504]the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsTop-notch Academic Programs Project of Jiangsu Higher Education Institutionsthe Jiangsu Province“Collaborative Innovation Center for Advanced Industrial Fermentation”Industry Development Programthe National First-Class Discipline Program of Light Industry Technology and Engineering[LITE2018-09]。
文摘(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1 that efficiently transforms 4-hydroxy-2-butanone to(R)-1,3-butanediol was isolated from soil samples. Based on morphological, physiological, and biochemical tests and 5.8 S-internal transcribed spacer sequencing, the strain was identified as Pichia kudriavzevii QC-1. The reaction conditions were optimized to 35 ℃, pH 8.0, rotation speed 200 rpm, and 6:5 mass ratio of glucose to 4-hydroxy-2-butanone. Evaluation of the effects of 4-hydroxy-2-butanone concentrations on yield and cell survival rate showed that 85.60 g·L^-1 product accumulated, with an enantiomeric excess of more than 99%, when 30 g·L^-14-hydroxy-2-butanone was added at 0, 10, and 30 h in a 3-L bioreactor. Thus, strain QC-1 showed excellent catalytic activity and stereoselectivity for the synthesis of(R)-1,3-butanediol from 4-hydroxy-2-butanone.
文摘The reduction reagents prepared from sodium borohydride, I-2 and a catalytic amount of chiral ferrocenyl amino alcohols 2a-e have been successfully applied to the enantioselective reduction of ketones. The optically active secondary alcohols were obtained in moderate enantiomeric excess and high chemical yield.
基金Project supported by the National Natural Science Foundation of China (No. 20172038) and Youth Science Foundation of Sichuan University.
文摘A series of novel N-squaramidoacid ligands were prepared conveniently. Without converting to corresponding amino alcohols, these ligands could be used in asymmetric borane reduction of prochiral aromatic ketones to give secondary alcohols in good to excellent enantiomeric excesses. The results showed that N-squaramidoacids are more efficient ligands than N-sulfonyl amino acids. N-Squaryl proline was proved to be an excellent ligand in this catalytic asymmetric process.
基金This work was supported by, the NNSFC.!(29972012)
文摘Two new type of 1,3,2-oxazaborolidines were prepared from (Is,2s)-2-amino-1-(4-nitrophenyl)-propane-1-3-diol and were used as catalyst in the asymmetric reduction of acetophenone. The influence of the reaction temperature as well as the effect of the structure of catalyst on the enantioselectivity was investigated. The origin of the products' configuration was discussed.
基金Project supported by the National Natural Science Foundation of China (29790127) and Chinese Academy of Sciences.
文摘Easily available D-(+)-camphor-derived chiral mercapto-alcohols 2 and 3 were employed for catalytic asymmetric borane reduction of aromatic ketones. Moderate enantioselectivities with e.e. 20.2–72.1% were obtained with 10 mol% catalyst. Opposite asymmetric induction was achieved' when mercapto-alcohols 2 and 3 were used.