For the first time,metal hydrogen sulfates and phosphates/silica gel have been studied as efficient and powerful solid acid catalysts in the ring opening of epoxides with thiocyanate anion.The most significant result ...For the first time,metal hydrogen sulfates and phosphates/silica gel have been studied as efficient and powerful solid acid catalysts in the ring opening of epoxides with thiocyanate anion.The most significant result was obtained by Al(HSO4)3/SiO2which afforded the corresponding β-hydroxy thiocyanates under mild reaction conditions and in very short reaction times.The cheapness, availability of the catalyst,ease of procedure and work-up make this method attractive for the organic synthesis.展开更多
Using four β-cyclodextrin derivatives, 2,6-di-O-benzyl-3-O-heptanonyl-β-CD, 2,6-di- O-benzyl-3-O-octanonyl-β-CD, 2,3-di-O-benzyl-6-O-heptanonyl-β-CD, and 2,3-di-O-benzyl -6-O- octanonyl-β-CD, as chiral stationary...Using four β-cyclodextrin derivatives, 2,6-di-O-benzyl-3-O-heptanonyl-β-CD, 2,6-di- O-benzyl-3-O-octanonyl-β-CD, 2,3-di-O-benzyl-6-O-heptanonyl-β-CD, and 2,3-di-O-benzyl -6-O- octanonyl-β-CD, as chiral stationary phases of capillary gas chromatography (CGC), the enantiomers of Sharpless epoxides were well separated. The enantiomer excess values (e.e.%) of some chiral Sharpless epoxides were also determined successfully using these CDs.展开更多
Allylation of terminal epoxides(1)to give the homoallylic alcohols(2)and bishomoallylic alcohols(3)can be carried out successfully by allyl bromide and metallic zinc or tin.The effect of substituents on epoxides was s...Allylation of terminal epoxides(1)to give the homoallylic alcohols(2)and bishomoallylic alcohols(3)can be carried out successfully by allyl bromide and metallic zinc or tin.The effect of substituents on epoxides was studied.展开更多
Silk fabrics is finished with epoxide TDEA or TDEB. By the determination of washing fastness, DSC, IR spectrum and amino acid contents tests, TDEA or TDEB is confirmed to react with silk fibroin. By means of tests of ...Silk fabrics is finished with epoxide TDEA or TDEB. By the determination of washing fastness, DSC, IR spectrum and amino acid contents tests, TDEA or TDEB is confirmed to react with silk fibroin. By means of tests of silk fibroin swelling and solubility in some solvents, crosslinking reactions between TDEA or TDEB and silk fibroin arc further proved, which is obviously responsible to the increase of wet-crease recovery of silk fabrics finished with epoxide TDEA or TDEB.展开更多
A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α',α"-N-hexakis(triethylammoniummethylene chloride)-...A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α',α"-N-hexakis(triethylammoniummethylene chloride)-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Over the past few years, dimethyl carbonate (DMC) has been proven to be an efficient methylating, methoxylating, and methoxycarbonylating agent in organic syntheses, in which DMC is used to replace the toxic methyl ...Over the past few years, dimethyl carbonate (DMC) has been proven to be an efficient methylating, methoxylating, and methoxycarbonylating agent in organic syntheses, in which DMC is used to replace the toxic methyl halides, dimethyl sulfate or carbon monoxide, and so forth. Furthermore, DMC has been used in the syntheses of polycarbonates and polyurethane to develop the nonphosgene routes Therefore, DMC has become one of the most important compounds in the development of green synthetic chemistry.展开更多
Macroporous resin (D201)-supported quartemary ammonium bisulfate (D201-HSO4) was prepared and effectively used in catalyzing the hydrolysis of epoxides or aziridines under mild and non-metal conditions to give the...Macroporous resin (D201)-supported quartemary ammonium bisulfate (D201-HSO4) was prepared and effectively used in catalyzing the hydrolysis of epoxides or aziridines under mild and non-metal conditions to give the corresponding 1,2-diols and β-amino alcohols in high yields. The catalyst was facilely prepared and recyclable.展开更多
Lewis acidic guanidinium ionic liquid(LAGIL) 2c was used as a novel, efficient and recyclable catalyst for aminolysis of epoxides under solvent-free and room temperature conditions, giving the corresponding β-amino...Lewis acidic guanidinium ionic liquid(LAGIL) 2c was used as a novel, efficient and recyclable catalyst for aminolysis of epoxides under solvent-free and room temperature conditions, giving the corresponding β-amino alcohols with moderate to excellent regioselectivity(up to 91:9) in high yields(up to 97%). In addition, LAGIL 2c was recycled three times without any loss of catalytic activity and selectivity to the product.展开更多
The asymmetric ring-opening of epoxides with dithiophosphorus acids catalyzed by a (salen)Ti(Ⅳ) complex formed in situ from the reaction of Ti(OPr-i)4 and the chiral Schiff base derived from (1R,2R)-(+)-di...The asymmetric ring-opening of epoxides with dithiophosphorus acids catalyzed by a (salen)Ti(Ⅳ) complex formed in situ from the reaction of Ti(OPr-i)4 and the chiral Schiff base derived from (1R,2R)-(+)-diaminocyclohexane was realized. The resulting products were obtained with low to good enantioselectivity (up to 73% ee).展开更多
The conformations and relative configurations of four epoxides of α-amido cyclohexenes have been determined by the combination of molecular modeling and NMR decoupling technique, cis-Epoxides were deduced from the vi...The conformations and relative configurations of four epoxides of α-amido cyclohexenes have been determined by the combination of molecular modeling and NMR decoupling technique, cis-Epoxides were deduced from the vicinal coupling constants calculated from the torsional angles H(1)-C(1)-C(2)-H(2) in modeling models by means of Karplus equation and observed by decoupling technique. The crystal structure of cis-4-nitro-N-(7-oxabicyclo[4.1.0]hept-2-yl)benzamide further confirms this assignment.展开更多
The chemical and microbiological hydrolyses of epoxide compounds of acetylene series have been comparatively carried out. It has been shown that as distinguished from chemical one in microbiological hydrolysis along w...The chemical and microbiological hydrolyses of epoxide compounds of acetylene series have been comparatively carried out. It has been shown that as distinguished from chemical one in microbiological hydrolysis along with corresponding optically active glycols, ketoalcohols of acetylene series are also formed. It has been also defined that the synthesized glycols of acetylene series have bactericide properties related to sulfate-reducing bacteria at concentration of 100 - 200 mg/l. It has been established that an introduction of electron-acceptor chlorine atoms in molecules influence on decreasing of bactericide activity of acetylene glycols.展开更多
A highly efficient asymmetric allylic alkylation of cyclic and acyclic carbon nucleophiles with vinyl epoxides has been developed,which exhibits good functional group compatibility,high atomic and step economy.This pr...A highly efficient asymmetric allylic alkylation of cyclic and acyclic carbon nucleophiles with vinyl epoxides has been developed,which exhibits good functional group compatibility,high atomic and step economy.This protocol utilizes a strategy of synergistic catalysis with a chiral N,N'-dioxide/Ni~Ⅱ complex and an achiral Pd~0 catalyst,generating a series of multisubstituted allylic alcohols with a quaternary carbon stereocenter in high yield and excellent regio-,Z/E-and enantioselectivity under mild conditions.Further transformations of the product demonstrate the potential utility of this protocol in the synthesis of allyl alcohol derivatives and natural product analogues.Experimental studies revealed that the N,N′-dioxide/metal complexes play an important role in controlling the Z/E-and enantioselectivity.The density functional theory(DFT) calculations further demonstrated that multiple C–H···π interactions between the aromatic rings of the two substrates and the amide moiety in the ligand stabilized the dominant transition state.展开更多
Pain is often debilitating,and current treatments are neither universally efficacious nor without risks.Transient receptor potential(TRP)ion channels offer alternative targets for pain relief,but little is known about...Pain is often debilitating,and current treatments are neither universally efficacious nor without risks.Transient receptor potential(TRP)ion channels offer alternative targets for pain relief,but little is known about the regulation or identities of endogenous TRP ligands that affect inflammation and pain.Here,transcriptomic and targeted lipidomic analysis of damaged tissue from the mouse spinal nerve ligation(SNL)-induced chronic pain model revealed a time-dependent increase in Cyp1b1 mRNA and a concurrent accumulation of 8,9-epoxyeicosatrienoic acid(EET)and 19,20-EpDPA post injury.Production of 8,9-EET and 19,20-EpDPA by human/mouse CYP1B1 was confirmed in vitro,and 8,9-EET and 19,20-EpDPA selectively and dose-dependently sensitized and activated TRPA1 in overexpressing HEK-293 cells and Trpa1-expressing/AITC-responsive cultured mouse peptidergic dorsal root ganglia(DRG)neurons.TRPA1 activation by 8,9-EET and 19,20-EpDPA was attenuated by the antagonist A967079,and mouse TRPA1 was more responsive to 8,9-EET and 19,20-EpDPA than human TRPA1.This latter effect mapped to residues Y933,G939,and S921 of TRPA1.Intra-plantar injection of 19,20-EpDPA induced acute mechanical,but not thermal hypersensitivity in mice,which was also blocked by A967079.Similarly,Cyp1b1-knockout mice displayed a reduced chronic pain phenotype following SNL injury.These data suggest that manipulation of the CYP1B1-oxylipin-TRPA1 axis might have therapeutic benefit.展开更多
Epoxides are important chemicals and used in multiple fields.The conventional thermal-catalytic production of epoxides consumes a large amount of energy and generates abundant carbon emissions.Therefore,sustainable ma...Epoxides are important chemicals and used in multiple fields.The conventional thermal-catalytic production of epoxides consumes a large amount of energy and generates abundant carbon emissions.Therefore,sustainable manufacturing technologies are highly desired.Taking advantage of renewable electricity to drive electrochemical epoxidation reactions provides a novel approach to generating value-added products in the chemicals sector.This review describes the current progress of selective electrochemical oxidation of olefins to epoxides,which is categorized according to the different reaction mechanisms.The halide-mediated method is first discussed,followed by an overview of electrochemical epoxidations with H_(2)O and O_(2)-derived H_(2)O_(2).Moreover,the existing problems in this fast-growing field and future developing directions are pointed out.This review hopes to provide inspiration for the design of electrocatalysts,electrode materials,and electrolyzers for the electrochemical production of epoxides in a sustainable manner.展开更多
Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge,because most o...Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge,because most of the catalysts exhibit poor tolerance to chain transfer agent(CTA).In this contribution,we demonstrated that potassium acetate(KOAc)and 18-crown-6(18-C-6)combination has great potential in the synthesis of diverse polyester polyols with controllable molecular weight and high-end group fidelity.Com-pared with KOAc,KOAc/18-C-6 pair could induce a much faster chain transfer between the active and dormant chains,and thus produce polyester polyols with narrow and monomodal distribution.In addition,polyester polyols could be efficiently prepared in laboratory by using commercially available cyclic anhydride without further purification(containing about 2%diacid residual as CTA)with an extremely low catalyst loading([catalyst pair]:[anhydride]:[epoxide]=1:50000:250000,[catalyst pair]=0.0004 mol%).KOAc/18-C-6 could also promote the self-switchable copolymerization of cyclic anhydride/epoxide/cyclic ester mixtures.Ring-opening copolymerization of cyclic ester was initiated automatically after the full conversion of cyclic anhydride,finally producing polyester polyols with ABA-type block structure.展开更多
Epoxides are one of the most important intermediates used in the production of valuable chemicals. Traditional preparation methods often rely on hazardous oxidants or extensive fossil fuel-powered thermal catalytic sy...Epoxides are one of the most important intermediates used in the production of valuable chemicals. Traditional preparation methods often rely on hazardous oxidants or extensive fossil fuel-powered thermal catalytic systems, resulting in significant waste production and CO_(2) emissions. Solar-driven photo(electro)chemistry is an emerging option for achieving the environmentally-friendly synthesis of epoxides. In this review, we firstly summarize the fundamental understanding of epoxidation reactions among various systems, including molecular catalysis, heterogeneous thermal catalysis and electrocatalysis. Then, we focus on the recent advances in the synthesis of epoxides achieved by photo(electro)chemical approaches. This review is concluded by the rational design of photoelectrochemical systems towards efficient epoxide synthesis.展开更多
A versatile heteropoly acid(H_(3)PMo_(12)O_(40))-catalyzed coupling of diarylmethanols with epoxides was established for the synthesis of polyaryl-substituted aldehydes.Furthermore,the catalytic system was also suitab...A versatile heteropoly acid(H_(3)PMo_(12)O_(40))-catalyzed coupling of diarylmethanols with epoxides was established for the synthesis of polyaryl-substituted aldehydes.Furthermore,the catalytic system was also suitable for the reaction of diarylmethanols and diols/aldehydes.The application of such an earthabundant,readily accessible,and nontoxic catalyst provides a green approach for the construction of polyaryl-substituted aldehydes.展开更多
A simple and efficient method for the synthesis of pyrazoles through a silicotungstic acid (H_(4)SiW_(12)O_(40))-catalyzed cyclization of epoxides/aldehydes and sulfonyl hydrazides has been developed. Various epoxides...A simple and efficient method for the synthesis of pyrazoles through a silicotungstic acid (H_(4)SiW_(12)O_(40))-catalyzed cyclization of epoxides/aldehydes and sulfonyl hydrazides has been developed. Various epoxides/aldehydes were smoothly reacted with sulfonyl hydrazides to furnish regioselectivity 3,4-disubstituted 1H-pyrazoles. The application of such an earth-abundant, readily accessible, and nontoxic catalyst provides a green approach for the construction of 3,4-disubstituted 1H-pyrazoles. A plausible reaction mechanism has been proposed on the basis of control experiments, GC-MS and DFT calculations.展开更多
This paper presents a versatile reagent for epoxide cleavage.The allyltin tribromide could act as a novel and easily prepared allylation reagent and halide atom donor to convert epoxides to the corresponding homoallyl...This paper presents a versatile reagent for epoxide cleavage.The allyltin tribromide could act as a novel and easily prepared allylation reagent and halide atom donor to convert epoxides to the corresponding homoallyl alcohols and halohydrins in high yields with excellent regioselectivities under mild reaction conditions,respectively.It could also act as a Lewis acid to catalyze the ring opening reactions of epoxides with alcohols.展开更多
基金the Shahid Chamran University Research Council for partial financial support of this work
文摘For the first time,metal hydrogen sulfates and phosphates/silica gel have been studied as efficient and powerful solid acid catalysts in the ring opening of epoxides with thiocyanate anion.The most significant result was obtained by Al(HSO4)3/SiO2which afforded the corresponding β-hydroxy thiocyanates under mild reaction conditions and in very short reaction times.The cheapness, availability of the catalyst,ease of procedure and work-up make this method attractive for the organic synthesis.
基金This work was kindly supported by the National Natural Science Foundation of China(No.30471153,30170621and 21023478).
文摘Using four β-cyclodextrin derivatives, 2,6-di-O-benzyl-3-O-heptanonyl-β-CD, 2,6-di- O-benzyl-3-O-octanonyl-β-CD, 2,3-di-O-benzyl-6-O-heptanonyl-β-CD, and 2,3-di-O-benzyl -6-O- octanonyl-β-CD, as chiral stationary phases of capillary gas chromatography (CGC), the enantiomers of Sharpless epoxides were well separated. The enantiomer excess values (e.e.%) of some chiral Sharpless epoxides were also determined successfully using these CDs.
文摘Allylation of terminal epoxides(1)to give the homoallylic alcohols(2)and bishomoallylic alcohols(3)can be carried out successfully by allyl bromide and metallic zinc or tin.The effect of substituents on epoxides was studied.
文摘Silk fabrics is finished with epoxide TDEA or TDEB. By the determination of washing fastness, DSC, IR spectrum and amino acid contents tests, TDEA or TDEB is confirmed to react with silk fibroin. By means of tests of silk fibroin swelling and solubility in some solvents, crosslinking reactions between TDEA or TDEB and silk fibroin arc further proved, which is obviously responsible to the increase of wet-crease recovery of silk fabrics finished with epoxide TDEA or TDEB.
基金the partial support of this work by Shahid Chamran Research Council
文摘A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α',α"-N-hexakis(triethylammoniummethylene chloride)-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金Supported by the National Natural Science Foundation of China(No20473043)
文摘Over the past few years, dimethyl carbonate (DMC) has been proven to be an efficient methylating, methoxylating, and methoxycarbonylating agent in organic syntheses, in which DMC is used to replace the toxic methyl halides, dimethyl sulfate or carbon monoxide, and so forth. Furthermore, DMC has been used in the syntheses of polycarbonates and polyurethane to develop the nonphosgene routes Therefore, DMC has become one of the most important compounds in the development of green synthetic chemistry.
文摘Macroporous resin (D201)-supported quartemary ammonium bisulfate (D201-HSO4) was prepared and effectively used in catalyzing the hydrolysis of epoxides or aziridines under mild and non-metal conditions to give the corresponding 1,2-diols and β-amino alcohols in high yields. The catalyst was facilely prepared and recyclable.
文摘Lewis acidic guanidinium ionic liquid(LAGIL) 2c was used as a novel, efficient and recyclable catalyst for aminolysis of epoxides under solvent-free and room temperature conditions, giving the corresponding β-amino alcohols with moderate to excellent regioselectivity(up to 91:9) in high yields(up to 97%). In addition, LAGIL 2c was recycled three times without any loss of catalytic activity and selectivity to the product.
基金the National Natural Science Foundation of China(No.20472033)the Ph.D Programs of Ministry of Education of China for generous financial support for our programs.
文摘The asymmetric ring-opening of epoxides with dithiophosphorus acids catalyzed by a (salen)Ti(Ⅳ) complex formed in situ from the reaction of Ti(OPr-i)4 and the chiral Schiff base derived from (1R,2R)-(+)-diaminocyclohexane was realized. The resulting products were obtained with low to good enantioselectivity (up to 73% ee).
文摘The conformations and relative configurations of four epoxides of α-amido cyclohexenes have been determined by the combination of molecular modeling and NMR decoupling technique, cis-Epoxides were deduced from the vicinal coupling constants calculated from the torsional angles H(1)-C(1)-C(2)-H(2) in modeling models by means of Karplus equation and observed by decoupling technique. The crystal structure of cis-4-nitro-N-(7-oxabicyclo[4.1.0]hept-2-yl)benzamide further confirms this assignment.
文摘The chemical and microbiological hydrolyses of epoxide compounds of acetylene series have been comparatively carried out. It has been shown that as distinguished from chemical one in microbiological hydrolysis along with corresponding optically active glycols, ketoalcohols of acetylene series are also formed. It has been also defined that the synthesized glycols of acetylene series have bactericide properties related to sulfate-reducing bacteria at concentration of 100 - 200 mg/l. It has been established that an introduction of electron-acceptor chlorine atoms in molecules influence on decreasing of bactericide activity of acetylene glycols.
基金supported by the National Natural Science Foundation of China (U19A2014)Sichuan University(2020SCUNL204)。
文摘A highly efficient asymmetric allylic alkylation of cyclic and acyclic carbon nucleophiles with vinyl epoxides has been developed,which exhibits good functional group compatibility,high atomic and step economy.This protocol utilizes a strategy of synergistic catalysis with a chiral N,N'-dioxide/Ni~Ⅱ complex and an achiral Pd~0 catalyst,generating a series of multisubstituted allylic alcohols with a quaternary carbon stereocenter in high yield and excellent regio-,Z/E-and enantioselectivity under mild conditions.Further transformations of the product demonstrate the potential utility of this protocol in the synthesis of allyl alcohol derivatives and natural product analogues.Experimental studies revealed that the N,N′-dioxide/metal complexes play an important role in controlling the Z/E-and enantioselectivity.The density functional theory(DFT) calculations further demonstrated that multiple C–H···π interactions between the aromatic rings of the two substrates and the amide moiety in the ligand stabilized the dominant transition state.
基金funded by the Department of Defense [W81XWH-17-1-0413, USA]。
文摘Pain is often debilitating,and current treatments are neither universally efficacious nor without risks.Transient receptor potential(TRP)ion channels offer alternative targets for pain relief,but little is known about the regulation or identities of endogenous TRP ligands that affect inflammation and pain.Here,transcriptomic and targeted lipidomic analysis of damaged tissue from the mouse spinal nerve ligation(SNL)-induced chronic pain model revealed a time-dependent increase in Cyp1b1 mRNA and a concurrent accumulation of 8,9-epoxyeicosatrienoic acid(EET)and 19,20-EpDPA post injury.Production of 8,9-EET and 19,20-EpDPA by human/mouse CYP1B1 was confirmed in vitro,and 8,9-EET and 19,20-EpDPA selectively and dose-dependently sensitized and activated TRPA1 in overexpressing HEK-293 cells and Trpa1-expressing/AITC-responsive cultured mouse peptidergic dorsal root ganglia(DRG)neurons.TRPA1 activation by 8,9-EET and 19,20-EpDPA was attenuated by the antagonist A967079,and mouse TRPA1 was more responsive to 8,9-EET and 19,20-EpDPA than human TRPA1.This latter effect mapped to residues Y933,G939,and S921 of TRPA1.Intra-plantar injection of 19,20-EpDPA induced acute mechanical,but not thermal hypersensitivity in mice,which was also blocked by A967079.Similarly,Cyp1b1-knockout mice displayed a reduced chronic pain phenotype following SNL injury.These data suggest that manipulation of the CYP1B1-oxylipin-TRPA1 axis might have therapeutic benefit.
基金the National Key R&D Program of China(grant no.2021YFA1501503)the National Natural Science Foundation of China(grant nos.22121004,22250008,,22108197)+1 种基金the Haihe Laboratory of Sustainable Chemical Transformations(grant no.CYZC202107)the Program of Introducing Talents of Discipline to Universities(grant no.BP0618007),and the Xplorer Prize for financial support。
文摘Epoxides are important chemicals and used in multiple fields.The conventional thermal-catalytic production of epoxides consumes a large amount of energy and generates abundant carbon emissions.Therefore,sustainable manufacturing technologies are highly desired.Taking advantage of renewable electricity to drive electrochemical epoxidation reactions provides a novel approach to generating value-added products in the chemicals sector.This review describes the current progress of selective electrochemical oxidation of olefins to epoxides,which is categorized according to the different reaction mechanisms.The halide-mediated method is first discussed,followed by an overview of electrochemical epoxidations with H_(2)O and O_(2)-derived H_(2)O_(2).Moreover,the existing problems in this fast-growing field and future developing directions are pointed out.This review hopes to provide inspiration for the design of electrocatalysts,electrode materials,and electrolyzers for the electrochemical production of epoxides in a sustainable manner.
基金financial support from the National Natural Science Foundation of China(Nos.52222302 and 51973156).
文摘Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge,because most of the catalysts exhibit poor tolerance to chain transfer agent(CTA).In this contribution,we demonstrated that potassium acetate(KOAc)and 18-crown-6(18-C-6)combination has great potential in the synthesis of diverse polyester polyols with controllable molecular weight and high-end group fidelity.Com-pared with KOAc,KOAc/18-C-6 pair could induce a much faster chain transfer between the active and dormant chains,and thus produce polyester polyols with narrow and monomodal distribution.In addition,polyester polyols could be efficiently prepared in laboratory by using commercially available cyclic anhydride without further purification(containing about 2%diacid residual as CTA)with an extremely low catalyst loading([catalyst pair]:[anhydride]:[epoxide]=1:50000:250000,[catalyst pair]=0.0004 mol%).KOAc/18-C-6 could also promote the self-switchable copolymerization of cyclic anhydride/epoxide/cyclic ester mixtures.Ring-opening copolymerization of cyclic ester was initiated automatically after the full conversion of cyclic anhydride,finally producing polyester polyols with ABA-type block structure.
基金supported by the National Key R&D Program of China (2022YFA1505000)the National Natural Science Foundation of China (22072158)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (XDB36000000)CAS Project for Young Scientists in Basic Research YSBR-004。
文摘Epoxides are one of the most important intermediates used in the production of valuable chemicals. Traditional preparation methods often rely on hazardous oxidants or extensive fossil fuel-powered thermal catalytic systems, resulting in significant waste production and CO_(2) emissions. Solar-driven photo(electro)chemistry is an emerging option for achieving the environmentally-friendly synthesis of epoxides. In this review, we firstly summarize the fundamental understanding of epoxidation reactions among various systems, including molecular catalysis, heterogeneous thermal catalysis and electrocatalysis. Then, we focus on the recent advances in the synthesis of epoxides achieved by photo(electro)chemical approaches. This review is concluded by the rational design of photoelectrochemical systems towards efficient epoxide synthesis.
基金the financial support from the National Natural Science Foundation of China(Nos.21871026,21971224)Research Found of East China University of Technology(Nos.DHBK2019265,DHBK2019267,DHBK2019264)。
文摘A versatile heteropoly acid(H_(3)PMo_(12)O_(40))-catalyzed coupling of diarylmethanols with epoxides was established for the synthesis of polyaryl-substituted aldehydes.Furthermore,the catalytic system was also suitable for the reaction of diarylmethanols and diols/aldehydes.The application of such an earthabundant,readily accessible,and nontoxic catalyst provides a green approach for the construction of polyaryl-substituted aldehydes.
基金financially supported by the National Natural Science Foundation of China (Nos. 22001034 and 21804019)the Open Fund of the Jiangxi Province Key Laboratory of Synthetic Chemistry (No. JXSC202008)the Research Found of East China University of Technology (Nos. DHBK2019264, DHBK2019265 and DHBK2019267)。
文摘A simple and efficient method for the synthesis of pyrazoles through a silicotungstic acid (H_(4)SiW_(12)O_(40))-catalyzed cyclization of epoxides/aldehydes and sulfonyl hydrazides has been developed. Various epoxides/aldehydes were smoothly reacted with sulfonyl hydrazides to furnish regioselectivity 3,4-disubstituted 1H-pyrazoles. The application of such an earth-abundant, readily accessible, and nontoxic catalyst provides a green approach for the construction of 3,4-disubstituted 1H-pyrazoles. A plausible reaction mechanism has been proposed on the basis of control experiments, GC-MS and DFT calculations.
文摘This paper presents a versatile reagent for epoxide cleavage.The allyltin tribromide could act as a novel and easily prepared allylation reagent and halide atom donor to convert epoxides to the corresponding homoallyl alcohols and halohydrins in high yields with excellent regioselectivities under mild reaction conditions,respectively.It could also act as a Lewis acid to catalyze the ring opening reactions of epoxides with alcohols.