The construction of secondary alkylsilanes is a challenging subject in the synthetic community.The cross-coupling provides a practical solution to address this problem,but it typically relies on organometallic species...The construction of secondary alkylsilanes is a challenging subject in the synthetic community.The cross-coupling provides a practical solution to address this problem,but it typically relies on organometallic species.Herein,we report an Mn-mediated reductive C(sp^(3))-Si coupling to synthesize these compounds from alkyl and silyl electrophiles.This approach avoids the requirement for activation of Si-Cl by transition metals and thus allows for the coupling of various common chlorosilanes.The reaction proceeds under mild conditions and shows good functional group compatibility.The method offers access toα-silylated organophosphorus and sulfones with a scope that is complementary to those obtained from the established methods.展开更多
Transition-metal catalyzed reductive carbosilylation of alkenes with carbon and silyl electrophiles has gained considerable attention for synthetic chemists recently,because it avoids air-and moisture-sensitive pre-pr...Transition-metal catalyzed reductive carbosilylation of alkenes with carbon and silyl electrophiles has gained considerable attention for synthetic chemists recently,because it avoids air-and moisture-sensitive pre-prepared organometallic reagents used.However,current carbon electrophiles are limited to alkyl or aryl bromides.Therefore,developing new synthetic approaches by choosing more easily available carbon electrophiles is still in high demand.Herein,we describe a nickel-catalyzed protocol that enables alkylsilylation of acrylonitrile with chlorosilanes and alkyl carboxylic acids via NHPI esters for the construction of various alkylsilanes,in which abundant and easy-accessible carboxylic acids were employed as the new alkyl electrophile sources,overcoming current limitations.This represents the first example of utilizing carboxylic acid as the alkyl reagent in reductive silylative alkylation of alkenes,thus providing a valuable complement to existing methodologies for the synthesis of a variety of organosilanes with diverse structures.Our approach also showcases broad substrate scope(including primary,secondary and tertiary carboxylic acids),good functional group compatibility(tolerating halides,heterocycles,Boc-protected amine,ester,ketone,terminal and internal alkenes,and terminal alkyne)and offers the capability for post-modification of complex agrochemical and pharmaceuticals.In addition,gram-scale reaction further demonstrates the applicable potential of the developed method.Overall,this protocol not only expands the boundaries of reductive difunctionalization reactions of alkenes but also enriches the synthetic toolbox for alkylsilane compounds preparation.展开更多
Montmorillonite was modified by chlorosilane derivatives (trimethylchlorosilane and tert butyldimethylchlorosilane) bas^ed on the reaction between OH group and chlorosilane. Fourier transformed infrared spec...Montmorillonite was modified by chlorosilane derivatives (trimethylchlorosilane and tert butyldimethylchlorosilane) bas^ed on the reaction between OH group and chlorosilane. Fourier transformed infrared spectra (FTIR) confirmed that chlorosilanes did react with the OH groups of montmorillonite. The effect of reaction time and dispersing agents on the intercalation was studied by wide angle X ray diffraction (WAXD) method. Further experiments proved that there is no reactive OH group on the surface of layers in the interlayer galleries of montmorillonite. The cation exchange capacity (CEC) of montmorillonites was measured, showing that after modification by chlorosilane derivatives, CEC values drastically decreased. The dispersibility measurements of montmorillonites were conducted, which showed that the dispersibility of modified montmorillonites both in H 2O and toluene were improved due to the decrease of attractions of particles and layers.展开更多
The reductive cross-coupling between C(aryl)—O and Si—Cl bonds is of much importance as a valuable strategy for the construction of C(aryl)—Si bonds but has remained a great challenge.Herein,we report a reductive c...The reductive cross-coupling between C(aryl)—O and Si—Cl bonds is of much importance as a valuable strategy for the construction of C(aryl)—Si bonds but has remained a great challenge.Herein,we report a reductive cross-coupling of diaryl ethers and chlorosilanes via strong electrophilic C(aryl)—O and Si—Cl bonds cleavage by iron catalysis,which constitutes an efficient protocol for the synthesis of a range of functionalized arylsilanes.The combination of low cost FeCl2 as the precatalyst and iPrMgCl as the reductant shows high activity in the successive cleavage of unactivated C(aryl)—O bonds of diaryl ethers and strong electrophilic Si—Cl bonds of chlorosilanes,allowing their cross-coupling in a reductive fashion.The low-valent iron species generated in situ by reduction of FeCl2 with iPrMgCl was proposed,which prefers to initially cleavage the C(aryl)—O bond of diaryl ethers with the chelation help of an o-amide auxiliary.展开更多
A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative ...A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.展开更多
基金the National Natural Science Foundation of China for its financial support(No.22071084).
文摘The construction of secondary alkylsilanes is a challenging subject in the synthetic community.The cross-coupling provides a practical solution to address this problem,but it typically relies on organometallic species.Herein,we report an Mn-mediated reductive C(sp^(3))-Si coupling to synthesize these compounds from alkyl and silyl electrophiles.This approach avoids the requirement for activation of Si-Cl by transition metals and thus allows for the coupling of various common chlorosilanes.The reaction proceeds under mild conditions and shows good functional group compatibility.The method offers access toα-silylated organophosphorus and sulfones with a scope that is complementary to those obtained from the established methods.
基金the financial support of the"Thousand Talents Plan"Youth Program,the National Natural Science Foundations of China(22101136,22478200,224B2802)the Fundamental Research Funds for the Central Universities(DUT23LAB612,DUT25RC(3)049)the Foundation of Guizhou Educational Committee(No.qianjiaoji[2023]088).
文摘Transition-metal catalyzed reductive carbosilylation of alkenes with carbon and silyl electrophiles has gained considerable attention for synthetic chemists recently,because it avoids air-and moisture-sensitive pre-prepared organometallic reagents used.However,current carbon electrophiles are limited to alkyl or aryl bromides.Therefore,developing new synthetic approaches by choosing more easily available carbon electrophiles is still in high demand.Herein,we describe a nickel-catalyzed protocol that enables alkylsilylation of acrylonitrile with chlorosilanes and alkyl carboxylic acids via NHPI esters for the construction of various alkylsilanes,in which abundant and easy-accessible carboxylic acids were employed as the new alkyl electrophile sources,overcoming current limitations.This represents the first example of utilizing carboxylic acid as the alkyl reagent in reductive silylative alkylation of alkenes,thus providing a valuable complement to existing methodologies for the synthesis of a variety of organosilanes with diverse structures.Our approach also showcases broad substrate scope(including primary,secondary and tertiary carboxylic acids),good functional group compatibility(tolerating halides,heterocycles,Boc-protected amine,ester,ketone,terminal and internal alkenes,and terminal alkyne)and offers the capability for post-modification of complex agrochemical and pharmaceuticals.In addition,gram-scale reaction further demonstrates the applicable potential of the developed method.Overall,this protocol not only expands the boundaries of reductive difunctionalization reactions of alkenes but also enriches the synthetic toolbox for alkylsilane compounds preparation.
文摘Montmorillonite was modified by chlorosilane derivatives (trimethylchlorosilane and tert butyldimethylchlorosilane) bas^ed on the reaction between OH group and chlorosilane. Fourier transformed infrared spectra (FTIR) confirmed that chlorosilanes did react with the OH groups of montmorillonite. The effect of reaction time and dispersing agents on the intercalation was studied by wide angle X ray diffraction (WAXD) method. Further experiments proved that there is no reactive OH group on the surface of layers in the interlayer galleries of montmorillonite. The cation exchange capacity (CEC) of montmorillonites was measured, showing that after modification by chlorosilane derivatives, CEC values drastically decreased. The dispersibility measurements of montmorillonites were conducted, which showed that the dispersibility of modified montmorillonites both in H 2O and toluene were improved due to the decrease of attractions of particles and layers.
基金financial support from the National Natural Science Foundation of China(21901206)Postdoctoral Science Foundation of China(2022M712589)+2 种基金General key R&D Projects in Shaanxi Province(2023-YBGY-321)Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0826)Fundamental Research Funds for the Central Universities and the Haihe Laboratory of Sustainable Chemical Transformation.
文摘The reductive cross-coupling between C(aryl)—O and Si—Cl bonds is of much importance as a valuable strategy for the construction of C(aryl)—Si bonds but has remained a great challenge.Herein,we report a reductive cross-coupling of diaryl ethers and chlorosilanes via strong electrophilic C(aryl)—O and Si—Cl bonds cleavage by iron catalysis,which constitutes an efficient protocol for the synthesis of a range of functionalized arylsilanes.The combination of low cost FeCl2 as the precatalyst and iPrMgCl as the reductant shows high activity in the successive cleavage of unactivated C(aryl)—O bonds of diaryl ethers and strong electrophilic Si—Cl bonds of chlorosilanes,allowing their cross-coupling in a reductive fashion.The low-valent iron species generated in situ by reduction of FeCl2 with iPrMgCl was proposed,which prefers to initially cleavage the C(aryl)—O bond of diaryl ethers with the chelation help of an o-amide auxiliary.
基金Supported by the National Natural Science Foundation of China(21306088)National Key Technologies R&D Program of China(2015BAD15B07)+1 种基金State Key Laboratory of Chemical Engineering(SKL-Ch E-13A01,Tsinghua University,China)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,China)
文摘A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.
