The Experts below are selected from a list of 150 Experts worldwide ranked by ideXlab platform
Mingzhong Cai - One of the best experts on this subject based on the ideXlab platform.
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A recyclable and reusable K2PtCl4/Xphos-SO3Na/PEG-400/H2O system for highly regio- and Stereoselective hydrosilylation of terminal alkynes
Green Chemistry, 2018Co-Authors: Bin Huang, Tao Yan, Mingzhong CaiAbstract:K2PtCl4/Xphos-SO3Na in a mixture of poly(ethylene glycol) (PEG-400) and water is shown to be a highly regio- and Stereoselective Catalyst for the hydrosilylation of terminal alkynes with hydrosilanes. The reaction could be conducted under mild conditions, yielding a variety of functionalized β-(E)-vinylsilanes in good to excellent yields with a total β-(E)-selectivity. The isolation of the products is readily performed by extraction with cyclohexane and more importantly, both expensive K2PtCl4 and Xphos-SO3Na in a PEG-400/H2O system could be easily recycled and reused at least eight times without any loss of catalytic activity.
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Diphosphino-functionalized MCM-41 anchored palladium(0) complex as an efficient Catalyst for Heck arylation of conjugated alkenes with aryl halides
Catalysis Communications, 2007Co-Authors: Mingzhong Cai, Junchao ShaAbstract:Abstract Diphosphino-functionalized MCM-41 anchored palladium(0) complex (denoted as MCM-41-2P-Pd(0)) was conveniently synthesized from commercially available and cheap γ-aminopropyltriethoxysilane via immobilization on MCM-41, followed by reacting with diphenylphosphinomethanol and palladium chloride and then the reduction with hydrazine hydrate. XRD and XPS spectroscopies were employed to characterize the title palladium complex. It was found that this complex is a highly active and Stereoselective Catalyst for Heck arylation of conjugated alkenes with aryl halides and can be reused many times without loss of activity.
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MCM-41-supported poly(γ-mercaptopropylsiloxane palladium(0)) complex as an efficient Catalyst for Heck arylation of conjugated alkenes with aryl halides
Reactive and Functional Polymers, 2007Co-Authors: Mingzhong CaiAbstract:Abstract MCM-41-supported poly(γ-mercaptopropylsiloxane palladium(0)) complex [MCM-41-SH-Pd(0)] was conveniently synthesized from commercially available and cheap γ-mercaptopropyltriethoxysilane via immobilization on MCM-41, followed by reacting with palladium chloride and then the reduction with hydrazine hydrate. XRD and XPS spectroscopy were employed to characterize the title palladium complex. It was found that this complex is a highly active and Stereoselective Catalyst for Heck arylation of conjugated alkenes with aryl halides and can be reused many times without loss of activity.
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The first MCM-41-supported thioether palladium(0) complex: A highly active and Stereoselective Catalyst for Heck arylation of olefins with aryl halides
Journal of Molecular Catalysis A-chemical, 2006Co-Authors: Mingzhong Cai, Jianwen JiangAbstract:The first MCM-41-supported thioether palladium(0) complex has been synthesized from 3-(2-cyanoethylsulfanyl)propyltriethoxysilane via immobilization on MCM-41, followed by reacting with palladium chloride, and then the reduction with hydrazine hydrate. It was found that this complex has not only high activity and stereoselectivity for arylation reaction of conjugated alkenes with aryl iodides or activated aryl bromides, but also can efficiently catalyze the arylation reaction of conjugated alkenes with unactivated bromoarenes. This polymeric palladium Catalyst can be easily recovered from the products and reused at least 10 times without loss of activity.
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Synthesis of silica-supported poly-ω-(methylseleno)undecylsiloxane palladium(0) complex and its catalytic properties for Heck arylation of alkenes
Journal of Molecular Catalysis A-chemical, 2004Co-Authors: Mingzhong Cai, Gang Liu, Jun ZhouAbstract:A silica-supported poly-ω-(methylseleno)undecylsiloxane palladium(0) complex has been prepared from ω-chloroundecyltriethoxysilane via immobilization on fumed silica, followed by reacting with sodium methylselenolate in ethanol and palladium chloride in acetone and then the reduction with hydrazine hydrate in ethanol. The complex is a highly active and Stereoselective Catalyst for arylation of conjugated alkenes with aryl halides. This polymeric palladium Catalyst can be recovered and reused.
Ying-yan Jiang - One of the best experts on this subject based on the ideXlab platform.
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The asymmetric hydration of 1-octene to (S)-(+)-2-octanol with a biopolymer–metal complex, silica-supported chitosan–cobalt complex
Reactive and Functional Polymers, 2004Co-Authors: Lei Xue, De-jun Zhou, Li Tang, Mei-yu Huang, Ying-yan JiangAbstract:Abstract A new biopolymer-non-noble metal Catalyst, silica-supported chitosan–cobalt complex (SiO 2 –CS–Co), has been prepared by a simple method and found to be a high Stereoselective Catalyst for asymmetric hydration of 1-octene to (S)-(+)-2-octanol amounted to 97.8%ee when fitting conditions were selected. This Catalyst was very stable and could be reused several times without any remarkable change in catalytic activity and optical selectivity. Obviously, the present work has provided a more economical alternative way for the preparation of a chiral 2-octanol.
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Asymmetric hydrogenation of diketones catalyzed by magnesium oxide‐supported chitosan–Rh complex
Polymers for Advanced Technologies, 2003Co-Authors: Da‐qing Zhou, Mei-yu Huang, Yan‐hong Zhang, Ying-yan JiangAbstract:MgO-supported chitosan–Rh complex (MgO-CS-Rh) has been prepared and found to be a highly Stereoselective Catalyst for the asymmetric hydrogenation of some diketones to corresponding chiral alcohols, such as 2,3-butanedione to (2S,3S)-(+)-2,3-butanediol and 2,4-pentanedione to (2S,4S)-(+)-2,4-pentanediol at room temperature and under 1 atm H2. The optical yield was greatly affected by the Rh content in the complex, the solvent and the reaction temperature. The optical yields of (2S,3S)-(+)-2,3-butanediol and (3S,4S)-(+)-2,4-pentanediol obtained were 87% and 81.2%, respectively. The chiral chitosan–Rh complex Catalyst was very easy to prepare, and could be reused without noticeable change in its optical catalytic activity. Copyright © 2003 John Wiley & Sons, Ltd.
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Catalytic behaviors of silica-supported chitin–platinum complex for asymmetric hydrogenation of α-phenylethanol
Journal of Molecular Catalysis A: Chemical, 2000Co-Authors: Guo-li Yuan, Mei-yu Huang, Mao-ya Yin, Ting-ting Jiang, Ying-yan JiangAbstract:Abstract Silica-supported chitin–platinum complex (SiO2–CT–Pt) has been prepared and found to be a high Stereoselective Catalyst for asymmetric hydrogenation of racemic α-phenylethanol to R-(+)-1-cyclohexyl ethanol at 30°C and under an atmospheric hydrogen pressure. The optical selectivity of R-(+)-1-cyclohexyl ethanol amounted to 100% when a fitting condition was selected. In this case, the yield and optical selectivity were affected greatly by many factors, such as Pt content in SiO2–CT–Pt complex, the reaction temperature, the solvent, and the amount of the additive of hydrochloric acid, etc. SiO2–CT–Pt Catalyst also has shown high stability. The optical selectivity for R-(+)-1-cyclohexyl ethanol was almost keeping at 100% when the Catalyst was reused for many times. Moreover, SiO2–CT–Pt complex is an economical chiral Catalyst. The chitin is an abundant natural biopolymer and the procedure for preparation of the complex is very simple.
Xiaoming Zheng - One of the best experts on this subject based on the ideXlab platform.
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MCM‐41 Supported Aminopropylsiloxane Palladium Acetate Complex: A Highly Active and Stereoselective Catalyst for Heck Reaction
Chinese Journal of Chemistry, 2010Co-Authors: Jian-min Zhou, Renxian Zhou, Shaofen Zhao, Xiaoming ZhengAbstract:A new MCM-41 supported aminopropylsiloxane palladium acetate was prepared and characterized. This Catalyst is highly active and Stereoselective for Heck reaction at 70°C.
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MCM-41 supported aminopropylsiloxane palladium(0) complex: a highly active and Stereoselective Catalyst for Heck reaction
Journal of Molecular Catalysis A-chemical, 2001Co-Authors: Jian-min Zhou, Renxian Zhou, Shaofen Zhao, Xiaoming ZhengAbstract:Abstract A new MCM-41 supported aminopropylsiloxane palladium(0) complex was prepared and characterized. The Catalyst is highly active and Stereoselective for Heck reaction at 70 °C.
Jean-françois Carpentier - One of the best experts on this subject based on the ideXlab platform.
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Recent Advances in Metal-Mediated Stereoselective Ring-Opening Polymerization of Functional Cyclic Esters towards Well-defined Poly(hydroxy acid)s: From Stereoselectivity to Sequence‐Control
Chemistry - A European Journal, 2020Co-Authors: Rama M. Shakaroun, Sophie M. Guillaume, Jean-françois CarpentierAbstract:Poly(hydroxy acid)s are a family of biocompatible and (bio)degradable polyesters with various outcomes in different domains of application. To date, poly(hydroxy acid)s are best prepared by ring-opening polymerization (ROP) of the corresponding cyclic esters. Using racemic chiral monomers featuring side-chain groups enables to access, providing a Stereoselective Catalyst/initiator system is implemented, stereoregular functional polymers, thereby improving their physico-chemical properties and ultimately widening their range of uses. Here, we highlight a few important advances in metal-mediated Stereoselective ROP of cyclic esters towards the synthesis of (functional) stereoregular poly(hydroxy acid)s that have recently been disclosed, emphasizing on (functional) β- and γ-lactones, diolide and O -carboxyanhydride (OCA) monomers and yttrium-based catalysis. Fine-tuning of the substituents flanked on the Catalyst ligand enables reaching poly(hydroxy acid)s with syndiotactic and also isotactic microstructures. The stereocontrol mechanisms at work and their probable origin, relying on steric but also electronic factors imparted in particular by the ligand substituents, are discussed. Taking advantages of such Stereoselective ROPs, original copoly(hydroxy acid)s with gradient or alternated patterns then become accessible from the use of mixtures of chemically different, oppositely configurated enantiopure monomers.
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Recent Advances in Metal‐Mediated Stereoselective Ring‐Opening Polymerization of Functional Cyclic Esters towards Well‐Defined Poly(hydroxy acid)s: From Stereoselectivity to Sequence‐Control
Chemistry (Weinheim an der Bergstrasse Germany), 2019Co-Authors: Rama M. Shakaroun, Sophie M. Guillaume, Jean-françois CarpentierAbstract:Poly(hydroxy acid)s are a family of biocompatible and (bio)degradable polyesters with various outcomes in different domains of application. To date, poly(hydroxy acid)s are best prepared by ring-opening polymerization (ROP) of the corresponding cyclic esters. Using racemic chiral monomers featuring side-chain groups enables to access, providing a Stereoselective Catalyst/initiator system is implemented, stereoregular functional polymers, thereby improving their physico-chemical properties and ultimately widening their range of uses. Here, we highlight a few important advances in metal-mediated Stereoselective ROP of cyclic esters towards the synthesis of (functional) stereoregular poly(hydroxy acid)s that have recently been disclosed, emphasizing on (functional) β- and γ-lactones, diolide and O -carboxyanhydride (OCA) monomers and yttrium-based catalysis. Fine-tuning of the substituents flanked on the Catalyst ligand enables reaching poly(hydroxy acid)s with syndiotactic and also isotactic microstructures. The stereocontrol mechanisms at work and their probable origin, relying on steric but also electronic factors imparted in particular by the ligand substituents, are discussed. Taking advantages of such Stereoselective ROPs, original copoly(hydroxy acid)s with gradient or alternated patterns then become accessible from the use of mixtures of chemically different, oppositely configurated enantiopure monomers.
Caisheng Song - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex and its catalytic properties for Heck arylation of conjugated alkenes
Reactive and Functional Polymers, 2004Co-Authors: Mingzhong Cai, Yizheng Huang, Hong Zhao, Caisheng SongAbstract:A silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex has been prepared from γ-chloropropyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide in THF and palladium chloride in acetone, and then the reduction with hydrazine hydrate in ethanol. The complex is a highly active and Stereoselective Catalyst for arylation of conjugated alkenes with aryl halides affording a variety of unsymmetrical trans-stilbenes and substituted trans-cinnamic acids in high yields. This polymeric palladium Catalyst can be recovered and reused.
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Silica-supported bidentate arsine palladium(0) complex: a highly active and Stereoselective Catalyst for arylation of conjugated alkenes
Journal of Organometallic Chemistry, 2003Co-Authors: Mingzhong Cai, Yizheng Huang, Hong Zhao, Caisheng SongAbstract:A silica-supported bidentate arsine palladium(0) complex has been prepared from 4-oxa-6,7-dichloroheptyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide and palladium chloride, and then the reduction with hydrazine hydrate. The complex has been characterized by X-ray photoelectron spectroscopy and it is a highly active and Stereoselective Catalyst for arylation of styrene and acrylic acid with aryl halides affording a variety of trans-stilbenes and substituted trans-cinnamic acids in high yields.