Trimethylsilylation of alcohols was achieved using 1,1,1,3,3,3-hexamethyldisilazane（HMDS） as silylating agent,in the presence of polyvinylpolypyrrolidonium tribromide in acetonitrile at room temperature.Also a varie...Trimethylsilylation of alcohols was achieved using 1,1,1,3,3,3-hexamethyldisilazane（HMDS） as silylating agent,in the presence of polyvinylpolypyrrolidonium tribromide in acetonitrile at room temperature.Also a variety of alcohols were converted into alkyl formates by ethyl formate and a catalytic amount of polyvinylpolypyrrolidonium tribromide under solvent free conditions at room temperature.展开更多
An environmentally friendly and transition metal-free method for the preparation of chiral α- hydroxysilanes was developed. Enantioselective addition of a silicon nucleophile to aromatic aldehydes in water was achiev...An environmentally friendly and transition metal-free method for the preparation of chiral α- hydroxysilanes was developed. Enantioselective addition of a silicon nucleophile to aromatic aldehydes in water was achieved by using a new hydroxyl-functionalized chiral carbene as catalyst, affording the corresponding products in good yields and moderate enantioselectivities.展开更多
A rhodium(Ⅲ)-catalyzed hydrosilylation/cyclization reaction of cyclohexadienone-tetheredα,β-unsaturated aldehydes(1,6-dienes)with triethylsilane is described,providing a series of cishydrobenzofurans,cis-hydroindol...A rhodium(Ⅲ)-catalyzed hydrosilylation/cyclization reaction of cyclohexadienone-tetheredα,β-unsaturated aldehydes(1,6-dienes)with triethylsilane is described,providing a series of cishydrobenzofurans,cis-hydroindoles,and cishydroindenes bearing silyl enol ether in good to excellent yields and excellent stereoselectivities.Additionally,the versatility of this method was demonstrated through a gram-scale experiment and various downstream transformations,highlighting its utility.展开更多
Effects of silylation on surface properties and catalytic performance of Zn-IM5 for butane aromatization were studied in this paper. Collidine-IR and NH3-TPD analyses revealed that the silylation treatment not only de...Effects of silylation on surface properties and catalytic performance of Zn-IM5 for butane aromatization were studied in this paper. Collidine-IR and NH3-TPD analyses revealed that the silylation treatment not only decreased the quantity of both strong and weak acid sites but also led to a slightly reduced intensity of weak acidity. Silylation of the catalyst promoted the selectivity of BTX by narrowing the channel and cutting the acidity. The effect of temperature of silylation and amount of Si loading were evaluated. The best condition has specified a temperature of 50 ℃ and a SiO_2 loading of 4.0%.展开更多
Background:Ursodeoxycholic acid is an important clinical drug in the treatment of liver disease.In our previous work,ursodeoxycholic acid was prepared by electroreduction of 7-ketolithocholic acid.The separation of ur...Background:Ursodeoxycholic acid is an important clinical drug in the treatment of liver disease.In our previous work,ursodeoxycholic acid was prepared by electroreduction of 7-ketolithocholic acid.The separation of ursodeoxycholic acid from the electroreduction product(47%(w/w)ursodeoxycholic acid)by silylation crystallization is described herein.Results:N,N-dimethylformamide was used as the solvent,whereas hexamethyldisilazane was the reaction agent.The optimal material ratio of electroreduction product/N,N-dimethylformamide/hexamethyldisilazane was found to be 1:10:2(w/v/v).The reaction proceeded for 2 h at 60℃,and the corresponding silylation derivative was separated by crystallization and pure ursodeoxycholic acid was recovered by 5%acid hydrolysis at 50℃ for 0.5 h.The maximum recovery and purity of ursodeoxycholic acid were 99.8%and 99.5%,respectively.Conclusion:Ursodeoxycholic acid with high purity and high recovery can be prepared directly.The developed method offers a potential application for large-scale production of ursodeoxycholic acid.展开更多
Binuclear platinum(Ⅲ)complexes were known for their high index of antitumor activity and a lower associated nephrotoxicity.However,the chemistry and reactivity of binuclear platinum(Ⅲ)compounds have not yet been exp...Binuclear platinum(Ⅲ)complexes were known for their high index of antitumor activity and a lower associated nephrotoxicity.However,the chemistry and reactivity of binuclear platinum(Ⅲ)compounds have not yet been explored to the same extent as those of platinum(Ⅱ)and platinum(Ⅳ)species.Here,we reported the first binuclear platinum-catalyzed hydrosilylation,monoborylation and diboration reaction of alkynes with excellent selectivity and yield.Moreover,the mechanistic investigation by control experiments,kinetic isotope effect(KIE)study,Hammett plots,NMR spectra,UV-vis spectra,and X-ray photoelectron spectroscopy(XPS)analysis reveal that the Pt(Ⅲ)2-catalyzed reactions pass through aσ-bond metathesis process rather than the two-electron redox processes of the mononuclear platinum catalysis.Moreover,there are two different rate-determining steps,in which the migratory insertion step dominates the rate of electron deficient substates andσ-bond metathesis process dominates electron rich counterparts,respectively.展开更多
In the past thirty years,transition metal catalyzed silylation of inert C–H bonds has attracted intensive attention due to the importance and wide use of organosilicon compounds.In this review,the silylation reaction...In the past thirty years,transition metal catalyzed silylation of inert C–H bonds has attracted intensive attention due to the importance and wide use of organosilicon compounds.In this review,the silylation reactions of inert C–H bonds catalyzed by transition metal complexes of Ir,Rh,Ru,Pt,Pd,Ni,and Sc,and the strategies utilized to access the site-selective C–H silylation products have been summarized.Furthermore,the mechanisms of C–H silylation reactions have been discussed briefly.展开更多
A photoelectrochemical approach for the C-H silylation of heteroarenes through dehydrogenation cross-coupling with H2 evolution has been developed.The photoelectrochemical C-H silylation depends on hydrogen atom trans...A photoelectrochemical approach for the C-H silylation of heteroarenes through dehydrogenation cross-coupling with H2 evolution has been developed.The photoelectrochemical C-H silylation depends on hydrogen atom transfer(HAT)from silanes to Cl-radical generated through the light-induced homolytic cleavage of Cl2,in which Cl2 was produced by electrochemical oxidation of chloride.A large number of silylated heterocyclic molecules are rapidly constructed in satisfactory yields without relying on oxidants and metal reagents.展开更多
A straightforward protocol for the synthesis of mono-fluorinated allenes via catalytic defluorinative silylation of the readily availableα,α-difluoroalkylalkynes with commercially available copper catalyst and phosp...A straightforward protocol for the synthesis of mono-fluorinated allenes via catalytic defluorinative silylation of the readily availableα,α-difluoroalkylalkynes with commercially available copper catalyst and phosphine ligand is described.A broad scope ofα,α-difluoroalkylalkynes were well accommodated and a gram-scale synthesis demonstrated the synthetic utility of this methodoglogy.展开更多
Metal catalyzed olefin hydrosilylation and metal mediated olefin polymerization are both of great academic and industrial importance, In this article, these two aspects are combined to prepare silicon- functionalized ...Metal catalyzed olefin hydrosilylation and metal mediated olefin polymerization are both of great academic and industrial importance, In this article, these two aspects are combined to prepare silicon- functionalized polyolefin materials, First, pyridine-diimine cobalt-catalyzed dehydrogenative silylations of various terminal olefins with alkylsilanes lead to the formation of a variety of allylsilanes at high yields, Then, the allylsilanes are copolymerized with ethylene using an α-diimine nickel catalyst, leading to the formation of branched polyolefins with high molecular weight and moderate comonomer incorporation. This subsequent catalytic process is an efficient strategy for the synthesis of silicon-functionalized polyolefins using widely available and inexpensive starting materials.展开更多
The catalytic radical-initiated asymmetric 1,2-aminosilylation of alkene with a hydrosilane under Cu(I)/CPA cooperative catalysis has been developed.This method features the use of hydrosilane as the reductive radical...The catalytic radical-initiated asymmetric 1,2-aminosilylation of alkene with a hydrosilane under Cu(I)/CPA cooperative catalysis has been developed.This method features the use of hydrosilane as the reductive radical precursor,enabling efficient access to skeletally diverse silicon-containing azaheterocycles including pyrrolidine,indoline and isoindoline bearing anα-tertiary stereocenter with high enantioselectivity.The key to the success includes the use of Cu(I)/CPA cooperative catalyst system and theβ-silicon effect of the silyl group to stabilize the in situ generated carbocation intermediate.展开更多
Silyl enol ethers are often obtained when the lithium enolates are trapped with chlorosilanes.Herein,we report a general method for the regio-and diasteroselective C-silylation of enolate enabled by theβ-boronyl grou...Silyl enol ethers are often obtained when the lithium enolates are trapped with chlorosilanes.Herein,we report a general method for the regio-and diasteroselective C-silylation of enolate enabled by theβ-boronyl group.The formation of five-membered chelation intermediate is key to the C-selective silylation and anti-selectivity.The operationally simple protocol provides a general and predictable access to theα-silylated esters.The synthetic versatility of the boron-silicon bifunctional products was demonstrated by down-stream transformations.展开更多
Main observation and conclusion A general synthesis of chiral 1,3-disubstituted allylsilanes is established through copper(I)-catalyzed asymmetric 1,4-conjugate silylation ofα,β-unsaturated sulfones and subsequent J...Main observation and conclusion A general synthesis of chiral 1,3-disubstituted allylsilanes is established through copper(I)-catalyzed asymmetric 1,4-conjugate silylation ofα,β-unsaturated sulfones and subsequent Julia-Kocienski olefination.By modification of McQuade's NHC ligand,the catalytic asymmetric conjugate silylation with a broad substrate scope is achieved in high enantioselectivity.展开更多
A strategy for Pd-catalyzed ortho-C–H silylation of biaryl aldehydes enabled by a transient auxiliary is presented. This protocol provides a broad range of ortho-silylated biaryl aldehydes in good yields. The silyl m...A strategy for Pd-catalyzed ortho-C–H silylation of biaryl aldehydes enabled by a transient auxiliary is presented. This protocol provides a broad range of ortho-silylated biaryl aldehydes in good yields. The silyl moiety can be further functionalized under mild conditions, rendering the silylated products useful building blocks. Notably, this protocol also offers an opportunity to establish a platform for expeditious synthesis of structurally diverse axially chiral biaryl aldehydes via sequential atroposelective interannular C–H functionalization/intraanular C–H silylation.展开更多
CO_2 incorporation into C-H bonds is an important and interesting topic. Herein a sequential protocol for C(sp)-H carboxylation by employing a metal-free C-H activation/catalytic silylation reaction in conjunction wit...CO_2 incorporation into C-H bonds is an important and interesting topic. Herein a sequential protocol for C(sp)-H carboxylation by employing a metal-free C-H activation/catalytic silylation reaction in conjunction with KO^tBu-mediated carboxylation with CO_2 was established, in which KO^t Bu catalyzes silylation of terminal alkynes to form alkynylsilanes at low temperature, and simultaneously mediates carboxylation of the alkynesilanes with atmospheric CO_2. Importantly, the carboxylation further promotes the silylation, which makes the whole reaction proceed very rapidly. Moreover, this methodology is simple and scalable, which is characterized by short reaction time, wide substrate scope, excellent functional-group tolerance and mild reaction conditions,affording a range of corresponding propiolic acid products in excellent yields in most cases. In addition, it also allows for a convenient ^(13)C-labeling through the use of ^(13)CO_2.展开更多
Herein,we describe an iron-catalyzed borylation and silylation of unactivated alkyl chlorides,delivering the tertiary,secondary,and primary alkylboronic esters,and secondary,primary alkylsilanes with high efficiency.T...Herein,we describe an iron-catalyzed borylation and silylation of unactivated alkyl chlorides,delivering the tertiary,secondary,and primary alkylboronic esters,and secondary,primary alkylsilanes with high efficiency.This protocol exhibits broad substrate scope and good functional group compatibility,allowing the efficient late-stage borylation of biorelevant compounds,thus offering an excellent platform in drug discovery and development.Preliminary mechanistic studies suggest that an alkyl radical was involved in this catalytic system.展开更多
Herein,we developed the first example of copper-catalyzed silicon radical-initiated 1,4-silylcyanation of unactivated 1,3-enynes,which provided an efficient method to access CN-bearing tri-and tetrasubstituted homoall...Herein,we developed the first example of copper-catalyzed silicon radical-initiated 1,4-silylcyanation of unactivated 1,3-enynes,which provided an efficient method to access CN-bearing tri-and tetrasubstituted homoallenylsilane derivatives in high yields with excellent regioselectivities.This protocol featured good functional group compatibility and broad substrate scopes,enabling the formation of C-Si bond under cheap copper catalyst with a low loading.Furthermore,this means showed potential application value in the late-stage functionalization of natural products.展开更多
Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely ...Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely heterogeneous sulfonic acid functionalized mesostructured SBA-15 in dichloromethane at ambient temperature. Primary, bulky secondary, tertiary, and phenolic hydroxyl functional groups were transformed to the corresponding trimethylsilyl ethers in excellent yields. The simple experimental procedure was accompanied by easy recovery and the catalyst was reusable (at least 18 reaction cycles); these are attractive features of this protocol.展开更多
Fluorinated poly（ethylene oxide） propyl-b-polydimethylsiloxane-b-propyl fluorinated poly（ethylene oxide） （FPEO-b-PDMS-b- FPEO） was synthesized by a free radical addition of carbon-hydrogen of polyether segments ...Fluorinated poly（ethylene oxide） propyl-b-polydimethylsiloxane-b-propyl fluorinated poly（ethylene oxide） （FPEO-b-PDMS-b- FPEO） was synthesized by a free radical addition of carbon-hydrogen of polyether segments of poly（ethylene oxide） propyl-b- polydimethylsiloxane-b-propyl poty（ethylene oxide） （PEO-b-PDMS-b-PEO） to hexafluoropropylene （HFP） using tert-butyl peroxypivalate as an initiator. In order to reduce the possibility of side reaction, the protection and deprotection via silylation were used for the end-hydroxyls in PEO-b-PDMS-b-PEO chain. The structure of Intermediates and FPEO-b-PDMS-b-FPEO was confirmed by means of Fourier transform infrared and 1H NMR spectroscopy. The effects of amount of initiator, reaction temperature and time on free radical addition were investigated in detail. 2009 Xing Yuan Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
文摘Trimethylsilylation of alcohols was achieved using 1,1,1,3,3,3-hexamethyldisilazane（HMDS） as silylating agent,in the presence of polyvinylpolypyrrolidonium tribromide in acetonitrile at room temperature.Also a variety of alcohols were converted into alkyl formates by ethyl formate and a catalytic amount of polyvinylpolypyrrolidonium tribromide under solvent free conditions at room temperature.
基金Financial support from the National Natural Science Foundation of China(Nos.21372144,81473085)Department of Science and Technology of Shandong Province
文摘An environmentally friendly and transition metal-free method for the preparation of chiral α- hydroxysilanes was developed. Enantioselective addition of a silicon nucleophile to aromatic aldehydes in water was achieved by using a new hydroxyl-functionalized chiral carbene as catalyst, affording the corresponding products in good yields and moderate enantioselectivities.
基金financial support from the National Key R&D Program of China(No.2022YFF1202600)the National Natural Science Foundation of China(Nos.22001172,22071155,and22371188)+4 种基金the Science and Technology Commission of Shanghai Municipality(Nos.20XD1403600 and 20400750300)the Shanghai Municipal Education Commission(No.2019-01-07-00-10-E00072)the Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(No.ZYYCXTD-202004)the Shanghai Municipal Health Commission/Shanghai Municipal Administration of Traditional Chinese Medicine[No.ZY(2021-2023)-0501]Organizational Key R&D Program of SHUTCM(No.2023YZZ01)。
文摘A rhodium(Ⅲ)-catalyzed hydrosilylation/cyclization reaction of cyclohexadienone-tetheredα,β-unsaturated aldehydes(1,6-dienes)with triethylsilane is described,providing a series of cishydrobenzofurans,cis-hydroindoles,and cishydroindenes bearing silyl enol ether in good to excellent yields and excellent stereoselectivities.Additionally,the versatility of this method was demonstrated through a gram-scale experiment and various downstream transformations,highlighting its utility.
基金financially supported by the Opening Project of the State Key Laboratory of Catalytic Material and Reaction Engineering of Sinopec Research Institute of Petroleum Processing. (No. 33600000-14-ZC0607-0010)
文摘Effects of silylation on surface properties and catalytic performance of Zn-IM5 for butane aromatization were studied in this paper. Collidine-IR and NH3-TPD analyses revealed that the silylation treatment not only decreased the quantity of both strong and weak acid sites but also led to a slightly reduced intensity of weak acidity. Silylation of the catalyst promoted the selectivity of BTX by narrowing the channel and cutting the acidity. The effect of temperature of silylation and amount of Si loading were evaluated. The best condition has specified a temperature of 50 ℃ and a SiO_2 loading of 4.0%.
文摘Background:Ursodeoxycholic acid is an important clinical drug in the treatment of liver disease.In our previous work,ursodeoxycholic acid was prepared by electroreduction of 7-ketolithocholic acid.The separation of ursodeoxycholic acid from the electroreduction product(47%(w/w)ursodeoxycholic acid)by silylation crystallization is described herein.Results:N,N-dimethylformamide was used as the solvent,whereas hexamethyldisilazane was the reaction agent.The optimal material ratio of electroreduction product/N,N-dimethylformamide/hexamethyldisilazane was found to be 1:10:2(w/v/v).The reaction proceeded for 2 h at 60℃,and the corresponding silylation derivative was separated by crystallization and pure ursodeoxycholic acid was recovered by 5%acid hydrolysis at 50℃ for 0.5 h.The maximum recovery and purity of ursodeoxycholic acid were 99.8%and 99.5%,respectively.Conclusion:Ursodeoxycholic acid with high purity and high recovery can be prepared directly.The developed method offers a potential application for large-scale production of ursodeoxycholic acid.
基金the National Natural Science Foundation of China(22071062,22271096 and 22001077)Guangdong Science and Technology Department(2023A1515011001,2021A1515012331)+1 种基金the Fundamental Research Funds for the Central Universities(2022ZYGXZR016)South China University of Technology for start-up funds,Guangdong Basic and Applied Basic Research Foundation(2024B1515040027).
文摘Binuclear platinum(Ⅲ)complexes were known for their high index of antitumor activity and a lower associated nephrotoxicity.However,the chemistry and reactivity of binuclear platinum(Ⅲ)compounds have not yet been explored to the same extent as those of platinum(Ⅱ)and platinum(Ⅳ)species.Here,we reported the first binuclear platinum-catalyzed hydrosilylation,monoborylation and diboration reaction of alkynes with excellent selectivity and yield.Moreover,the mechanistic investigation by control experiments,kinetic isotope effect(KIE)study,Hammett plots,NMR spectra,UV-vis spectra,and X-ray photoelectron spectroscopy(XPS)analysis reveal that the Pt(Ⅲ)2-catalyzed reactions pass through aσ-bond metathesis process rather than the two-electron redox processes of the mononuclear platinum catalysis.Moreover,there are two different rate-determining steps,in which the migratory insertion step dominates the rate of electron deficient substates andσ-bond metathesis process dominates electron rich counterparts,respectively.
基金financially supported by the National Natural Science Foundation of China(21322203,21272238,21472194)the National Basic Research Program of China(2012CB821600)
文摘In the past thirty years,transition metal catalyzed silylation of inert C–H bonds has attracted intensive attention due to the importance and wide use of organosilicon compounds.In this review,the silylation reactions of inert C–H bonds catalyzed by transition metal complexes of Ir,Rh,Ru,Pt,Pd,Ni,and Sc,and the strategies utilized to access the site-selective C–H silylation products have been summarized.Furthermore,the mechanisms of C–H silylation reactions have been discussed briefly.
基金the Natural Science Foundation of Zhejiang Province(LQ22B020005,LZ22B020003)the National Natural Science Foundation of China(22101201,22071171)for financial support of this work.
文摘A photoelectrochemical approach for the C-H silylation of heteroarenes through dehydrogenation cross-coupling with H2 evolution has been developed.The photoelectrochemical C-H silylation depends on hydrogen atom transfer(HAT)from silanes to Cl-radical generated through the light-induced homolytic cleavage of Cl2,in which Cl2 was produced by electrochemical oxidation of chloride.A large number of silylated heterocyclic molecules are rapidly constructed in satisfactory yields without relying on oxidants and metal reagents.
基金support of the National Natural Science Foundation of China(No.21871138)Distinguished Youth Foundation of Jiangsu province.
文摘A straightforward protocol for the synthesis of mono-fluorinated allenes via catalytic defluorinative silylation of the readily availableα,α-difluoroalkylalkynes with commercially available copper catalyst and phosphine ligand is described.A broad scope ofα,α-difluoroalkylalkynes were well accommodated and a gram-scale synthesis demonstrated the synthetic utility of this methodoglogy.
基金supported by the National Natural Science Foundation of China(21690071 and 51522306)
文摘Metal catalyzed olefin hydrosilylation and metal mediated olefin polymerization are both of great academic and industrial importance, In this article, these two aspects are combined to prepare silicon- functionalized polyolefin materials, First, pyridine-diimine cobalt-catalyzed dehydrogenative silylations of various terminal olefins with alkylsilanes lead to the formation of a variety of allylsilanes at high yields, Then, the allylsilanes are copolymerized with ethylene using an α-diimine nickel catalyst, leading to the formation of branched polyolefins with high molecular weight and moderate comonomer incorporation. This subsequent catalytic process is an efficient strategy for the synthesis of silicon-functionalized polyolefins using widely available and inexpensive starting materials.
基金supported by the National Natural Science Foundation of China(21722203,21831002,21801116,21572096)Shenzhen Special Funds for the Development of Biomedicine,Internet,New Energy,and New Material Industries(JCYJ20170412152435366,JCYJ20170307105638498,JCYJ20180302180235837)+1 种基金Guangdong Natural Science Foundation(2018A030310083)Shenzhen Nobel Prize Scientists Laboratory Project(C17783101)
文摘The catalytic radical-initiated asymmetric 1,2-aminosilylation of alkene with a hydrosilane under Cu(I)/CPA cooperative catalysis has been developed.This method features the use of hydrosilane as the reductive radical precursor,enabling efficient access to skeletally diverse silicon-containing azaheterocycles including pyrrolidine,indoline and isoindoline bearing anα-tertiary stereocenter with high enantioselectivity.The key to the success includes the use of Cu(I)/CPA cooperative catalyst system and theβ-silicon effect of the silyl group to stabilize the in situ generated carbocation intermediate.
基金Financial support was provided by the National Natural Science Foundation of China(Nos.22001210 and 21971202)the Natural Science Basic Research Plan of Shaanxi Province(2020JC-08)。
文摘Silyl enol ethers are often obtained when the lithium enolates are trapped with chlorosilanes.Herein,we report a general method for the regio-and diasteroselective C-silylation of enolate enabled by theβ-boronyl group.The formation of five-membered chelation intermediate is key to the C-selective silylation and anti-selectivity.The operationally simple protocol provides a general and predictable access to theα-silylated esters.The synthetic versatility of the boron-silicon bifunctional products was demonstrated by down-stream transformations.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(Nos.21672235,21871287,and 21922114)the Science and Technology Commission of Shanghai Municipality(No.20JC1417100)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000)CAS Key Laboratory of Synthetic Chemistry of Natural SubstancesShanghai Institute of Organic Chemistry.
文摘Main observation and conclusion A general synthesis of chiral 1,3-disubstituted allylsilanes is established through copper(I)-catalyzed asymmetric 1,4-conjugate silylation ofα,β-unsaturated sulfones and subsequent Julia-Kocienski olefination.By modification of McQuade's NHC ligand,the catalytic asymmetric conjugate silylation with a broad substrate scope is achieved in high enantioselectivity.
基金supported by the National Natural Science Foundation of China (21925109, 21772170)the Outstanding Young Talents of Zhejiang Province High-level Personnel of Special Support (ZJWR0108)+1 种基金the Fundamental Research Funds for the Central Universities (2018XZZX001-02)Zhejiang Provincial Natural Science Foundation (LR17B020001)。
文摘A strategy for Pd-catalyzed ortho-C–H silylation of biaryl aldehydes enabled by a transient auxiliary is presented. This protocol provides a broad range of ortho-silylated biaryl aldehydes in good yields. The silyl moiety can be further functionalized under mild conditions, rendering the silylated products useful building blocks. Notably, this protocol also offers an opportunity to establish a platform for expeditious synthesis of structurally diverse axially chiral biaryl aldehydes via sequential atroposelective interannular C–H functionalization/intraanular C–H silylation.
基金supported by the National Natural Science Foundation of China(21503239,21533011,21402208,21403252)
文摘CO_2 incorporation into C-H bonds is an important and interesting topic. Herein a sequential protocol for C(sp)-H carboxylation by employing a metal-free C-H activation/catalytic silylation reaction in conjunction with KO^tBu-mediated carboxylation with CO_2 was established, in which KO^t Bu catalyzes silylation of terminal alkynes to form alkynylsilanes at low temperature, and simultaneously mediates carboxylation of the alkynesilanes with atmospheric CO_2. Importantly, the carboxylation further promotes the silylation, which makes the whole reaction proceed very rapidly. Moreover, this methodology is simple and scalable, which is characterized by short reaction time, wide substrate scope, excellent functional-group tolerance and mild reaction conditions,affording a range of corresponding propiolic acid products in excellent yields in most cases. In addition, it also allows for a convenient ^(13)C-labeling through the use of ^(13)CO_2.
基金support from the National Natural Science Foundation of China(no.21801029)the Fundamental Research Funds for the Central Universities(no.2020CDJQY-A043)+4 种基金the Sichuan Key Laboratory of Medical Imaging(North Sichuan Medical College,no.SKLMI201901)the Strategic Cooperation of Science and Technology between Nanchong City and North Sichuan Medical College(nos.19SXHZ0441 and 19SXHZ0227)the Chongqing Postdoctoral Science Foundation(no.cstc2020jcyj-bsh0061)the China Postdoctoral Science Foundation(no.2020M673121)the Natural Science Foundation of Chongqing(no.cstc2019jcyj-msxmX0048).
文摘Herein,we describe an iron-catalyzed borylation and silylation of unactivated alkyl chlorides,delivering the tertiary,secondary,and primary alkylboronic esters,and secondary,primary alkylsilanes with high efficiency.This protocol exhibits broad substrate scope and good functional group compatibility,allowing the efficient late-stage borylation of biorelevant compounds,thus offering an excellent platform in drug discovery and development.Preliminary mechanistic studies suggest that an alkyl radical was involved in this catalytic system.
基金support of this work by the funding of the National Natural Science Foundation of China(No.22371269)the State Key Laboratory of Elementoorganic Chemistry Nankai University(No.202001)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0450301)the Open Project of Key Laboratory of Organosilicon Chemistry,and Material Technology of Ministry of Education,Hangzhou Normal University(No.KFJJ2022013)。
文摘Herein,we developed the first example of copper-catalyzed silicon radical-initiated 1,4-silylcyanation of unactivated 1,3-enynes,which provided an efficient method to access CN-bearing tri-and tetrasubstituted homoallenylsilane derivatives in high yields with excellent regioselectivities.This protocol featured good functional group compatibility and broad substrate scopes,enabling the formation of C-Si bond under cheap copper catalyst with a low loading.Furthermore,this means showed potential application value in the late-stage functionalization of natural products.
文摘Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely heterogeneous sulfonic acid functionalized mesostructured SBA-15 in dichloromethane at ambient temperature. Primary, bulky secondary, tertiary, and phenolic hydroxyl functional groups were transformed to the corresponding trimethylsilyl ethers in excellent yields. The simple experimental procedure was accompanied by easy recovery and the catalyst was reusable (at least 18 reaction cycles); these are attractive features of this protocol.
基金supports from the National Natural Science Foundation of China(No.50273035)and Hefei Ketian Chemical Industry Co.,Ltd.
文摘Fluorinated poly（ethylene oxide） propyl-b-polydimethylsiloxane-b-propyl fluorinated poly（ethylene oxide） （FPEO-b-PDMS-b- FPEO） was synthesized by a free radical addition of carbon-hydrogen of polyether segments of poly（ethylene oxide） propyl-b- polydimethylsiloxane-b-propyl poty（ethylene oxide） （PEO-b-PDMS-b-PEO） to hexafluoropropylene （HFP） using tert-butyl peroxypivalate as an initiator. In order to reduce the possibility of side reaction, the protection and deprotection via silylation were used for the end-hydroxyls in PEO-b-PDMS-b-PEO chain. The structure of Intermediates and FPEO-b-PDMS-b-FPEO was confirmed by means of Fourier transform infrared and 1H NMR spectroscopy. The effects of amount of initiator, reaction temperature and time on free radical addition were investigated in detail. 2009 Xing Yuan Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
