Heterocycle-braced cyclic peptides have demonstrated enhanced metabolic stability,increased potency and selectivity.Here,we present a rapid synthesis method for constructing Trp(C7)-alkene(E)-crosslinked cyclic peptid...Heterocycle-braced cyclic peptides have demonstrated enhanced metabolic stability,increased potency and selectivity.Here,we present a rapid synthesis method for constructing Trp(C7)-alkene(E)-crosslinked cyclic peptides with potent anti-proliferative activities against cancer cells,through C-H alkenylation and macrolactamization.This report addresses critical challenges associated with the installation and removal of the directing group N-Piv,configuration selectivity of the olefin,and intramolecular cyclization.No-tably,this method exhibits mild reaction conditions,traceless removal of the directing group,and high configuration selectivity.展开更多
Catalytic enantioselective alkenylation is an efficient method to construct chiral alkene molecules,but the asymmetric alkenylation of simple alkenes catalyzed by metal-free catalysts remains an elusive challenge.Here...Catalytic enantioselective alkenylation is an efficient method to construct chiral alkene molecules,but the asymmetric alkenylation of simple alkenes catalyzed by metal-free catalysts remains an elusive challenge.Herein,we reported an asymmetric alkenylation of benzoxazinones with diarylethylenes by utilizing a B(C_(6)F_(5))_(3)/chiral phosphoric acid catalyst.A broad of benzoxazinones and diarylethylenes with electron-withdrawing and electron-donating groups were tolerated(up to 95%yield and 97.5:2.5 e.r.)in the methodology under mild reaction conditions.Moreover,the synthetic utility was confirmed by the scaled-up reaction and transformations of the products.The mechanism was preliminarily explored by control reactions,nonlinear effect experiment and DFT calculations.展开更多
The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids （SO42？/meso‐La0.1Zr0.9Oδ） were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9O...The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids （SO42？/meso‐La0.1Zr0.9Oδ） were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9Oδcomposites, such as the molar ratio of the template to La and Zr metal ions （Nt/m）, molar ratio of ammonia to La and Zr metal ions （Na/m）, hydrothermal temperature （Thydro）, and hy‐drothermal time （thydro）. The effect of the textural features and acidic properties on the catalytic performance of solid acid catalysts for alkenylation of p‐xylene with phenylacetylene was investi‐gated. Various characterization techniques such as N2 physisorption, X‐ray diffraction, NH3 temper‐ature‐programmed desorption, and thermogravimetric analysis were employed to reveal the rela‐tionship between the nature of catalyst and its catalytic performance. It was found that the catalytic performance significantly depended on the textural features and acidic properties, which were strongly affected by preparation conditions of the meso‐La0.1Zr0.9Oδcomposite. Appropriate acidic sites and high accessibility were required to obtain satisfactory catalytic reactions for this reaction. It was also found that the average crystallite size of t‐ZrO2 affected by the preparation conditions had significant influence on the ultrastrong acidic sites of the catalysts. The optimized SO42？/meso‐La0.1Zr0.9Oδcatalyst exhibited much superior catalytic activity and coke‐resistant stabil‐ity. Moreover, the developed SO42？/meso‐La0.1Zr0.9Oδcatalyst demonstrated excellent catalytic per‐formance for alkenylation of diverse aromatics with phenylacetylene to their correspondingα‐arylstyrenes. Combining the previously established complete regeneration of used catalysts by a facile calcination process with the improved catalytic properties, the developed SO42？/meso‐La0.1Zr0.9Oδ solid acid could be a potential catalyst for industrial production ofα‐arylstyrenes through clean and atom efficient solid‐acid‐mediated Friedel‐Crafts alkenylation of diverse aromatics with phenylacetylene.展开更多
A ceria‐modified hierarchical Hβzeolite was prepared by a desilication‐dealumination procedure followed by ceria modification.The catalytic performance of the ceria‐modified and unmodified hierarchical Hβzeolite ...A ceria‐modified hierarchical Hβzeolite was prepared by a desilication‐dealumination procedure followed by ceria modification.The catalytic performance of the ceria‐modified and unmodified hierarchical Hβzeolite catalysts for alkenylation of p‐xylene with phenylacetylene was investigated.Various characterization techniques,including X‐ray diffraction,X‐ray fluorescence,nitrogen adsorption‐desorption,and NH3temperature‐programmed desorption,were used to examine the structure‐performance relationships.Our results show that the optimized ceria‐modified hierarchical Hβzeolite catalyst demonstrated higher catalytic activity,selectivity,and stability for alkenylation of p‐xylene with phenylacetylene than those of pristine Hβzeolite.This performance was attributed to more acidic sites and improved accessibility to active sites through larger pores,together with a higher mesoporous surface area and volume resulting from the hierarchical pore architecture and ceria modification.Thus,our5wt%CeO2‐Hβ‐B0.2A0.2catalyst shows great potential for producing alkenyl aromatics through solid acid catalyzed alkenylation.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved展开更多
In this work, a spherical hollow mesoporous silica(SHMS) with high surface area(902 m^2/g) and large mesopore volume(1.31 cm^3/g) was prepared via a facile and scalable two-step soft-hard dual templateassisted sol-gel...In this work, a spherical hollow mesoporous silica(SHMS) with high surface area(902 m^2/g) and large mesopore volume(1.31 cm^3/g) was prepared via a facile and scalable two-step soft-hard dual templateassisted sol-gel approach(OSDSG) by using glucose-derived carbon nano/micro particles(NMCP) as a hard template and cetyltrimethylammonium bromide(CTAB) as a soft template,respectively,in which the size-preselected carbon submicro-particle was used to replace ploymer sphere, and no extra precious additives like n-octadecyltrimethoxysilane(C18TMS). Supported phosphotungstic acid(PTA) catalysts on SHMS(PTA/SHMS) and on previously reported spherical mesoporous silica(PTA/SMS) with 25 wt% of PTA loading were prepared and employed as solid acid catalysts for diverse reactions. Transmission electron microscopy(TEM),N_2 adsorption-desorption, X-ray diffraction(XRD), and NH_3 temperatureprogrammed desorption(NH_3-TPD) techniques were employed to characterize the nature of carriers and supported PTA catalysts for revealing the structure-performance relationship. The developed PTA/SHMS catalyst demonstrates much higher catalytic activity than PTA/SMS for diverse reactions including alkenylation, esterification, alkylation, and benzylation, ascribed to the strengthened mass transfer and enlarged exposure degree of acidic sites to reactants those resulting from unique hollow and mesoporous morphology. Moreover, PTA/SHMS catalyst also exhibits outstanding catalytic performance for the diverse a-arylstyrenes via solid acid-mediated alkenylation. PTA/SHMS could be considered as a practical solid acid catalyst for diverse transformations.展开更多
Highly dispersed silicotungstic acid-derived WO_(3) composited with ZrO_(2) supported on SBA-_(15) (WZ/SBA-_(15)) as an ordered mesoporous solid acid catalyst was prepared via a facile incipient wetness impregnation (...Highly dispersed silicotungstic acid-derived WO_(3) composited with ZrO_(2) supported on SBA-_(15) (WZ/SBA-_(15)) as an ordered mesoporous solid acid catalyst was prepared via a facile incipient wetness impregnation (IWI) method that active ingredients, ZrO_(2) and WO_(3), were impregnated into the channels of SBA-_(15) simultaneously with a subsequent calcination process. The relationship between catalyst nature and performance was explored by high resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), FT-IR, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N_(2) adsorption-desorption, NH_(3) temperature-programmed desorption (NH_(3)-TPD), and FT-IR of pyridine adsorption (Py-IR) characterization techniques. The catalytic performance of W_(12)Z_(15)/SBA-_(15) is not only greater than that of single component solid acid catalysts, WO_(3)/SBA-_(15) and ZrO_(2)/SBA-_(15), but also W_(12)/Z_(15)/SBA-_(15) prepared by impregnating active ingredients, ZrO_(2) and WO_(3), into SBA-_(15) in sequence. The outstanding performance of W_(12)Z_(15)/SBA-_(15) is derived from the strong interaction between ZrO_(2) and WO_(3), which results in more acid sites, and relatively high specific surface area, large pore volume, and ordered mesoporous structure of SBA-_(15). The characterization and reaction results clearly demonstrate that the synergy of ZrO_(2) and WO_(3) has a clear boost for the alkenylation. The optimized W_(12)Z_(15)/SBA-_(15)-500 achieves a 99.4% conversion of phenylacetylene and a 92.3% selectivity of main product α-arylstyrene for the alkenylation of p-xylene with phenylacetylene, with very low level of oligomers producing at the same time. Moreover, W_(12)Z_(15)/SBA-_(15)-500 shows excellent catalytic stability and regeneration. Therefore, W_(12)Z_(15)/SBA-_(15)-500 is a promising solid acid catalyst for the alkenylation.展开更多
An efficient asymmetric alkenylation between 3-vinylindoles and isatin derivatives was developed under catalysis of a chiral copper complex.A series of optically active 3-alkenyl-3-substituted oxindoles were obtained ...An efficient asymmetric alkenylation between 3-vinylindoles and isatin derivatives was developed under catalysis of a chiral copper complex.A series of optically active 3-alkenyl-3-substituted oxindoles were obtained in excellent yields and stereoselectivities.The reaction mechanism was proposed and supported by DFT calculation.展开更多
Herein,a rapid alkenylation of quinoxalin-2(1H)-ones enabled by a combination of Mannich-type reaction and solar photocatalysis is demonstrated.A wide range of functional groups are compatible,affording the correspond...Herein,a rapid alkenylation of quinoxalin-2(1H)-ones enabled by a combination of Mannich-type reaction and solar photocatalysis is demonstrated.A wide range of functional groups are compatible,affording the corresponding products in moderate-to-good yields.Control experiments illustrate that the in situ generated^(1)O_(2)plays a central role in this reaction.This green and efficient strategy provides a practical solution for the synthesis of potentially bioactive compounds that containing a 3,4-dihydroquinoxalin-2(1H)-one structure.展开更多
Reactions involving alkenyl acetates offer cost-effective and environmentally friendly routes for alkene synthesis,yet their asymmetric variant remains elusive.Concurrently,asymmetric conjugate alkenylation predominan...Reactions involving alkenyl acetates offer cost-effective and environmentally friendly routes for alkene synthesis,yet their asymmetric variant remains elusive.Concurrently,asymmetric conjugate alkenylation predominantly centered on nucleophilic addition using alkenyl–M.This manuscript presents an asymmetric reductive conjugate alkenylation reaction involving alkenyl acetates.The method facilitates the enantioselective addition of keto alkenyl groups toα,β-enones,resulting in the formation of unsaturated diketones—a class of useful structural motifs that are challenging to access otherwise.The use of electron-rich Pyroxy ligand is essential for achieving both high reaction efficiency and enantioselectivity.展开更多
The catalytic enantioselective hydroalkenylation of olefins is an efficient and straightforward strategy for the rapid synthesis ofα-chiral olefins.The first example of cobalt-hydride catalyzed radical enantioselecti...The catalytic enantioselective hydroalkenylation of olefins is an efficient and straightforward strategy for the rapid synthesis ofα-chiral olefins.The first example of cobalt-hydride catalyzed radical enantioselective hydroalkenylation of vinyl arenes with readily available nucleophilic vinyl trifluoroborates is described.The reaction proceeds through a cobalthydride mediated hydrogen atom transfer followed by radical-polar crossover process,providing a series ofα-chiral olefins in excellent regio-and enantioselectivities with good functional group compatibility.Moreover,the participation of alkenyl fragment in this reaction substantially broadens its applicability and leads to structurally diverse products.This reaction provides a new efficient method for the synthesis of valuableα-chiral olefins by using nucleophilic alkenyl reagents.展开更多
Dirhodium(Ⅱ)complexes have achieved great success in organic synthesis,and fine-tuning their catalytic properties with various bridging ligands is well-investigated in carbene chemistry.However,combining dirhodium(Ⅱ...Dirhodium(Ⅱ)complexes have achieved great success in organic synthesis,and fine-tuning their catalytic properties with various bridging ligands is well-investigated in carbene chemistry.However,combining dirhodium(Ⅱ)with a sophisticated ligand as a catalyst in other reactions is still extremely challenging,especially for the asymmetric synthesis of valuable chiral molecules.Herein,we report a dirhodium(Ⅱ)/(S)-Me O-BIPHEP catalytic system for the challenging asymmetricβ-alkenylation ofα,β-unsaturated aldehydes,affording the corresponding chiral conjugate addition products in good yields with high enantioselectivities.A couple of drug-derived substrates were also compatible with the protocol,which has been successfully used to prepare biologically relevant pyranochromene compounds.Preliminary mechanistic studies suggested that the dirhodium core might remain intact over the catalytic cycle,and the chiral diphosphine ligand plays a key role in this novel reactivity and determining the high enantioselectivities of the asymmetric conjugate addition.展开更多
The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines via direct SIVfunctionalization is synthetically attractive but challenging due to the competitive reaction...The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines via direct SIVfunctionalization is synthetically attractive but challenging due to the competitive reaction of N-functionalization. Herein, we disclose a novel strain-release strategy to access stereospecific and chemoselective SIV-arylation and alkenylation of sulfinamides using arynes and strained cyclic alkynes. This method tolerates an unprecedented chemical diversity of functional groups attached to the nitrogen center(N-R). The origin of the high SIV-selectivity is elucidated by density functional theory calculations, suggesting a stepwise mechanism for the aryne substrates and a concerted mechanism for the cyclic alkynes.展开更多
A high-efficient and stereo-specific approach for the preparation of biologically important （E）-2-styryl-tetra- hydrobenzo[d]thiazoles has been developed via TMSC1 promoted direct sp3 C-H alkenylation of 2-methyl-5,...A high-efficient and stereo-specific approach for the preparation of biologically important （E）-2-styryl-tetra- hydrobenzo[d]thiazoles has been developed via TMSC1 promoted direct sp3 C-H alkenylation of 2-methyl-5,6-di- hydrobenzo[d]thiazol-7（4H）-one under metal-free conditions. Seventeen target compounds were synthesized in ex- cellent yields of 82%--98% under the optimal conditions of 300 mol% TMSCI at 110℃ for 2 h, and their chemical structures were elucidated by IR, NMR, ESI-MS, elemental analyses and X-ray crystallography analysis. A plausible mechanism was also proposed, and this method provided a good functional group conversion for the sp3 C-H substrates.展开更多
Herein,we report the first highly enantioselective Ni-catalyzed arylation and alkenylation of simple aldehydes using readily available and stable organoboronic esters.This protocol provides various chiral secondary al...Herein,we report the first highly enantioselective Ni-catalyzed arylation and alkenylation of simple aldehydes using readily available and stable organoboronic esters.This protocol provides various chiral secondary alcohols in high yields and enantioselectivities(up to 97% ee)with a broad scope of substrates,functional groups,and heterocycles.The use of a bulky N-heterocyclic carbene(NHC)ligand for nickel catalyst is the key to high enantiocontrol.The competitive Ni-catalyzed transformations,including Tishchenko reaction,dehydrogenation/hydrogenation reaction,and Suzuki-Miyaura couplings,are avoided.The excellent chemoselectivity is likely due to the application of mild base CsF and η^(2)-coordination of aldehydes with nickel.展开更多
Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to ...Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to the inevitable side reactions involving cycloaddition.Herein,the visible-light-mediated O-H functionalization reactions of alkenyl alcohols with diazo compounds were developed.This process competed favorably with the cycloaddition reaction.A series of multifunctional ethers were provided in low to high yields with aryldiazoacetates or 3-diazooxindoles.Biologically relevant spirooxindole-fused oxacycle could be easily accessed from the O-H functionalization product of alkenyl alcohol and 3-diazooxindole.展开更多
A visible-light-enabled method for the synthesis ofα-azidoketones has been developed via oxo-azidation of alkenyl silanes with trimethylsilylazide and molecular oxygen under mild conditions.The reaction could be carr...A visible-light-enabled method for the synthesis ofα-azidoketones has been developed via oxo-azidation of alkenyl silanes with trimethylsilylazide and molecular oxygen under mild conditions.The reaction could be carried out in gram scale.Various radical sources,including trifluoromethyl radical,thiocyanate radical,bromide radical,chlorine radical could partici-pate effectively instead of azide radical in the reaction.展开更多
Pyrazolidinones,as significant analogs ofβ-lactam antibiotics,have garnered substantial interest for their enantioselective synthesis.Azomethine imines,recognized as valuable building blocks for the construction of t...Pyrazolidinones,as significant analogs ofβ-lactam antibiotics,have garnered substantial interest for their enantioselective synthesis.Azomethine imines,recognized as valuable building blocks for the construction of these nitrogen-containing compounds,underscore the continuous pursuit of novel building blocks and reaction methodologies within the chemical community.In this paper,we present a cascade cyclization between alkenyl azomethine imines and furan-2(5H)-one to generate chiral coronal polyheterocyclic compounds with high yields and enantioselectivities,catalyzed by dipeptide-derived phosphonium salts.In-vitro biological activity assays highlight the potential of these chiral compounds in drug discovery.Additionally,density functional theory(DFT)calculations elucidate the pivotal role of phosphonium salts,demonstrating their cooperative activations via hydrogen bonding and ion-pairing interactions.展开更多
Main observation and conclusion A new Rh(Ⅲ)-catalyzed direct C—H alkenylation of 2,3-unsubstitued indoles with alkenyl borates through C—H activation followed by transmetallation was described.This protocol provide...Main observation and conclusion A new Rh(Ⅲ)-catalyzed direct C—H alkenylation of 2,3-unsubstitued indoles with alkenyl borates through C—H activation followed by transmetallation was described.This protocol provides an efficient method for the synthesis of terminal C2-alkenylindoles under mild conditions,and also shows broad substrate scope and high functional group tolerance with respect to both components.Furthermore,the C2-alkenylated indole can be easily transformed into carboline derivative,which is an important polycyclic indole moiety in natural products and drug molecules.展开更多
Chemoselective,living/controlled polymerizations of allyl methacrylate(AMA) and vinyl methacrylate(VMA) with/without methyl methacrylate(MMA) by using the phosphonium ylide/organoaluminum based Lewis pairs(LPs) have b...Chemoselective,living/controlled polymerizations of allyl methacrylate(AMA) and vinyl methacrylate(VMA) with/without methyl methacrylate(MMA) by using the phosphonium ylide/organoaluminum based Lewis pairs(LPs) have been realized.The P-ylide-2/AIMe(BHT)_(2)(Pylide-2=Ph_(3)P=CHMe and BHT=2,6-iBu_(2)-4-MeC_(6)H_(2)O) was demonstrated to be superior by which homopolymers PAMAs(M_(n)=27.6-111.5kg/mol and ■=1.14-1.25) and PVMAs(M_(n)=28.4-78.4 kg/mol and ■=1.12-1.18) and block copolymers PMMA-b-PAMA,PAMA-b-PVMA,PAMA-bPMMA,PMMA-b-PAMA-b-PMMA,PAMA-b-PMMA-b-PAMA,and PAMA-b-PVMA-b-PAMA were synthesized.In the polymerizations,all of the monomers were reacted by the conjugated ester vinyl groups leaving intactly the nonconjugated acryloxy groups.The pendant acryloxy groups attached to the main chain enable further to post-functionalization by the AIBN-induced radical "thiol-ene" reaction using PhCH_(2)SH.The thiolether side group-containing polymers PAMA-SCH_(2)Ph and PAMA-SCH_(2)Ph-b-PMMA-b-PAMA-SCH_(2)Ph were thus prepared.展开更多
Cesium carbonate was used as a base to achieve the desulfurization reaction of alkenyl sulfonium salts and phosphine oxides at room temperature,forming C(sp2)—P bonds.This method features simple operation,mild reacti...Cesium carbonate was used as a base to achieve the desulfurization reaction of alkenyl sulfonium salts and phosphine oxides at room temperature,forming C(sp2)—P bonds.This method features simple operation,mild reaction conditions,and good functional group compatibility,offering a straightforward and efficient preparation route for terminal vinyl phosphine oxides.展开更多
基金the National Key R&D Program of China(No.2022YFA1302900 to H.Liu)National Natural Science Foundation of China(Nos.82130105,22337003,82121005 to H.Liu+2 种基金and Nos.22177124,82322063 to J.Wang)Program of Shang-hai Academic Research Leader(No.23XD1460300 to J.Wang)the Lingang Laboratory(No.LG-GG-202204-02 to J.Wang)for supporting this work.We would like to acknowledge Shanghai Highline Therapeutics.
文摘Heterocycle-braced cyclic peptides have demonstrated enhanced metabolic stability,increased potency and selectivity.Here,we present a rapid synthesis method for constructing Trp(C7)-alkene(E)-crosslinked cyclic peptides with potent anti-proliferative activities against cancer cells,through C-H alkenylation and macrolactamization.This report addresses critical challenges associated with the installation and removal of the directing group N-Piv,configuration selectivity of the olefin,and intramolecular cyclization.No-tably,this method exhibits mild reaction conditions,traceless removal of the directing group,and high configuration selectivity.
基金National Natural Science Foundation of China(Nos.22193011,21971120 and 21933008)National Science&Technology Fundamental Resource Investigation Program of China(No.2018FY201200)for financial support.
文摘Catalytic enantioselective alkenylation is an efficient method to construct chiral alkene molecules,but the asymmetric alkenylation of simple alkenes catalyzed by metal-free catalysts remains an elusive challenge.Herein,we reported an asymmetric alkenylation of benzoxazinones with diarylethylenes by utilizing a B(C_(6)F_(5))_(3)/chiral phosphoric acid catalyst.A broad of benzoxazinones and diarylethylenes with electron-withdrawing and electron-donating groups were tolerated(up to 95%yield and 97.5:2.5 e.r.)in the methodology under mild reaction conditions.Moreover,the synthetic utility was confirmed by the scaled-up reaction and transformations of the products.The mechanism was preliminarily explored by control reactions,nonlinear effect experiment and DFT calculations.
基金financially supported by the National Natural Science Foundation of China (21276041)the Program for New Century Excellent Talents in University of Ministry of Education (NCET-12-0079)+1 种基金the Natural Science Foundation of Liaoning Province (2015020200)the Fundamental Research Funds for the Central Universities (DUT15LK41)~~
文摘The textural features and acidic properties of sulfated mesoporous lanthana‐zirconia solid acids （SO42？/meso‐La0.1Zr0.9Oδ） were efficiently tuned by modifying the conditions used to prepare the meso‐La0.1Zr0.9Oδcomposites, such as the molar ratio of the template to La and Zr metal ions （Nt/m）, molar ratio of ammonia to La and Zr metal ions （Na/m）, hydrothermal temperature （Thydro）, and hy‐drothermal time （thydro）. The effect of the textural features and acidic properties on the catalytic performance of solid acid catalysts for alkenylation of p‐xylene with phenylacetylene was investi‐gated. Various characterization techniques such as N2 physisorption, X‐ray diffraction, NH3 temper‐ature‐programmed desorption, and thermogravimetric analysis were employed to reveal the rela‐tionship between the nature of catalyst and its catalytic performance. It was found that the catalytic performance significantly depended on the textural features and acidic properties, which were strongly affected by preparation conditions of the meso‐La0.1Zr0.9Oδcomposite. Appropriate acidic sites and high accessibility were required to obtain satisfactory catalytic reactions for this reaction. It was also found that the average crystallite size of t‐ZrO2 affected by the preparation conditions had significant influence on the ultrastrong acidic sites of the catalysts. The optimized SO42？/meso‐La0.1Zr0.9Oδcatalyst exhibited much superior catalytic activity and coke‐resistant stabil‐ity. Moreover, the developed SO42？/meso‐La0.1Zr0.9Oδcatalyst demonstrated excellent catalytic per‐formance for alkenylation of diverse aromatics with phenylacetylene to their correspondingα‐arylstyrenes. Combining the previously established complete regeneration of used catalysts by a facile calcination process with the improved catalytic properties, the developed SO42？/meso‐La0.1Zr0.9Oδ solid acid could be a potential catalyst for industrial production ofα‐arylstyrenes through clean and atom efficient solid‐acid‐mediated Friedel‐Crafts alkenylation of diverse aromatics with phenylacetylene.
基金supported by the National Natural Science Foundation of China(21276041,U1610104)the Chinese Ministry of Education via the Program for New Century Excellent Talents in University(NCET-12-0079)~~
文摘A ceria‐modified hierarchical Hβzeolite was prepared by a desilication‐dealumination procedure followed by ceria modification.The catalytic performance of the ceria‐modified and unmodified hierarchical Hβzeolite catalysts for alkenylation of p‐xylene with phenylacetylene was investigated.Various characterization techniques,including X‐ray diffraction,X‐ray fluorescence,nitrogen adsorption‐desorption,and NH3temperature‐programmed desorption,were used to examine the structure‐performance relationships.Our results show that the optimized ceria‐modified hierarchical Hβzeolite catalyst demonstrated higher catalytic activity,selectivity,and stability for alkenylation of p‐xylene with phenylacetylene than those of pristine Hβzeolite.This performance was attributed to more acidic sites and improved accessibility to active sites through larger pores,together with a higher mesoporous surface area and volume resulting from the hierarchical pore architecture and ceria modification.Thus,our5wt%CeO2‐Hβ‐B0.2A0.2catalyst shows great potential for producing alkenyl aromatics through solid acid catalyzed alkenylation.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved
基金financially supported by the National Natural Science Foundation of China(Nos.21276041 and U1610104)by the Chinese Ministry of Education via the Program for New Century Excellent Talents in University(No. NCET-12-0079)
文摘In this work, a spherical hollow mesoporous silica(SHMS) with high surface area(902 m^2/g) and large mesopore volume(1.31 cm^3/g) was prepared via a facile and scalable two-step soft-hard dual templateassisted sol-gel approach(OSDSG) by using glucose-derived carbon nano/micro particles(NMCP) as a hard template and cetyltrimethylammonium bromide(CTAB) as a soft template,respectively,in which the size-preselected carbon submicro-particle was used to replace ploymer sphere, and no extra precious additives like n-octadecyltrimethoxysilane(C18TMS). Supported phosphotungstic acid(PTA) catalysts on SHMS(PTA/SHMS) and on previously reported spherical mesoporous silica(PTA/SMS) with 25 wt% of PTA loading were prepared and employed as solid acid catalysts for diverse reactions. Transmission electron microscopy(TEM),N_2 adsorption-desorption, X-ray diffraction(XRD), and NH_3 temperatureprogrammed desorption(NH_3-TPD) techniques were employed to characterize the nature of carriers and supported PTA catalysts for revealing the structure-performance relationship. The developed PTA/SHMS catalyst demonstrates much higher catalytic activity than PTA/SMS for diverse reactions including alkenylation, esterification, alkylation, and benzylation, ascribed to the strengthened mass transfer and enlarged exposure degree of acidic sites to reactants those resulting from unique hollow and mesoporous morphology. Moreover, PTA/SHMS catalyst also exhibits outstanding catalytic performance for the diverse a-arylstyrenes via solid acid-mediated alkenylation. PTA/SHMS could be considered as a practical solid acid catalyst for diverse transformations.
基金financially supported by the National Natural Science Foundation of China (No. 21276041)Chinese Ministry of Education via the Program for New Century Excellent Talents in University (No. NCET-12-0079)。
文摘Highly dispersed silicotungstic acid-derived WO_(3) composited with ZrO_(2) supported on SBA-_(15) (WZ/SBA-_(15)) as an ordered mesoporous solid acid catalyst was prepared via a facile incipient wetness impregnation (IWI) method that active ingredients, ZrO_(2) and WO_(3), were impregnated into the channels of SBA-_(15) simultaneously with a subsequent calcination process. The relationship between catalyst nature and performance was explored by high resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), FT-IR, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N_(2) adsorption-desorption, NH_(3) temperature-programmed desorption (NH_(3)-TPD), and FT-IR of pyridine adsorption (Py-IR) characterization techniques. The catalytic performance of W_(12)Z_(15)/SBA-_(15) is not only greater than that of single component solid acid catalysts, WO_(3)/SBA-_(15) and ZrO_(2)/SBA-_(15), but also W_(12)/Z_(15)/SBA-_(15) prepared by impregnating active ingredients, ZrO_(2) and WO_(3), into SBA-_(15) in sequence. The outstanding performance of W_(12)Z_(15)/SBA-_(15) is derived from the strong interaction between ZrO_(2) and WO_(3), which results in more acid sites, and relatively high specific surface area, large pore volume, and ordered mesoporous structure of SBA-_(15). The characterization and reaction results clearly demonstrate that the synergy of ZrO_(2) and WO_(3) has a clear boost for the alkenylation. The optimized W_(12)Z_(15)/SBA-_(15)-500 achieves a 99.4% conversion of phenylacetylene and a 92.3% selectivity of main product α-arylstyrene for the alkenylation of p-xylene with phenylacetylene, with very low level of oligomers producing at the same time. Moreover, W_(12)Z_(15)/SBA-_(15)-500 shows excellent catalytic stability and regeneration. Therefore, W_(12)Z_(15)/SBA-_(15)-500 is a promising solid acid catalyst for the alkenylation.
基金support from the National Natural Science Foundation of China(No.21772185)supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000).
文摘An efficient asymmetric alkenylation between 3-vinylindoles and isatin derivatives was developed under catalysis of a chiral copper complex.A series of optically active 3-alkenyl-3-substituted oxindoles were obtained in excellent yields and stereoselectivities.The reaction mechanism was proposed and supported by DFT calculation.
基金the Natural Science Foundation of Zhejiang Province(No.LY21B060009)the National Natural Science Foundation of China(No.21871071)for financial support.
文摘Herein,a rapid alkenylation of quinoxalin-2(1H)-ones enabled by a combination of Mannich-type reaction and solar photocatalysis is demonstrated.A wide range of functional groups are compatible,affording the corresponding products in moderate-to-good yields.Control experiments illustrate that the in situ generated^(1)O_(2)plays a central role in this reaction.This green and efficient strategy provides a practical solution for the synthesis of potentially bioactive compounds that containing a 3,4-dihydroquinoxalin-2(1H)-one structure.
基金supported by the National Natural Science Foundation of China(22271127,22071084)the Fundamental Research Funds for the Central Universities(lzujbky-2022-ey01)。
文摘Reactions involving alkenyl acetates offer cost-effective and environmentally friendly routes for alkene synthesis,yet their asymmetric variant remains elusive.Concurrently,asymmetric conjugate alkenylation predominantly centered on nucleophilic addition using alkenyl–M.This manuscript presents an asymmetric reductive conjugate alkenylation reaction involving alkenyl acetates.The method facilitates the enantioselective addition of keto alkenyl groups toα,β-enones,resulting in the formation of unsaturated diketones—a class of useful structural motifs that are challenging to access otherwise.The use of electron-rich Pyroxy ligand is essential for achieving both high reaction efficiency and enantioselectivity.
基金support from the National Natural Science Foundation of China(grant nos.22171043 and 22193012)the Fundamental Research Funds for the Central Universities-Excellent Youth Team Program(grant no.2412023YQ001).
文摘The catalytic enantioselective hydroalkenylation of olefins is an efficient and straightforward strategy for the rapid synthesis ofα-chiral olefins.The first example of cobalt-hydride catalyzed radical enantioselective hydroalkenylation of vinyl arenes with readily available nucleophilic vinyl trifluoroborates is described.The reaction proceeds through a cobalthydride mediated hydrogen atom transfer followed by radical-polar crossover process,providing a series ofα-chiral olefins in excellent regio-and enantioselectivities with good functional group compatibility.Moreover,the participation of alkenyl fragment in this reaction substantially broadens its applicability and leads to structurally diverse products.This reaction provides a new efficient method for the synthesis of valuableα-chiral olefins by using nucleophilic alkenyl reagents.
基金supported by the National Key R&D Program of China(2021YFA1500100)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0610000,XDB1180000)+6 种基金the National Natural Science Foundation of China(92256303,22171278,21821002)the Shanghai Science and Technology Committee(23ZR1482400)the Natural Science Foundation of Ningbo(2023J034)the Postdoctoral Fellowship Program of China Postdoctoral Science Foudation(GZC20232863)the China Postdoctoral Science Foundation(2024M763426)the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal Universitythe Research Funds of Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences。
文摘Dirhodium(Ⅱ)complexes have achieved great success in organic synthesis,and fine-tuning their catalytic properties with various bridging ligands is well-investigated in carbene chemistry.However,combining dirhodium(Ⅱ)with a sophisticated ligand as a catalyst in other reactions is still extremely challenging,especially for the asymmetric synthesis of valuable chiral molecules.Herein,we report a dirhodium(Ⅱ)/(S)-Me O-BIPHEP catalytic system for the challenging asymmetricβ-alkenylation ofα,β-unsaturated aldehydes,affording the corresponding chiral conjugate addition products in good yields with high enantioselectivities.A couple of drug-derived substrates were also compatible with the protocol,which has been successfully used to prepare biologically relevant pyranochromene compounds.Preliminary mechanistic studies suggested that the dirhodium core might remain intact over the catalytic cycle,and the chiral diphosphine ligand plays a key role in this novel reactivity and determining the high enantioselectivities of the asymmetric conjugate addition.
基金supported by the National Natural Science Foundation of China(22001065)the Science and Technology Foundation of Hunan Province(2021JJ30090)+3 种基金Guangdong Provincial Key Laboratory of Catalysis(2020B121201002)Shenzhen Science and Technology Program(KQTD20210811090112004)supported by Center for Computational Science and Engineering at SUSTechthe CHEM high-performance supercomputer cluster(CHEM-HPC)located at the Department of Chemistry,SUSTech。
文摘The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines via direct SIVfunctionalization is synthetically attractive but challenging due to the competitive reaction of N-functionalization. Herein, we disclose a novel strain-release strategy to access stereospecific and chemoselective SIV-arylation and alkenylation of sulfinamides using arynes and strained cyclic alkynes. This method tolerates an unprecedented chemical diversity of functional groups attached to the nitrogen center(N-R). The origin of the high SIV-selectivity is elucidated by density functional theory calculations, suggesting a stepwise mechanism for the aryne substrates and a concerted mechanism for the cyclic alkynes.
基金The authors thank the finance supported by the National Natural Science Foundation of China （No. 21272136）, and Scientific Research Innovation Founda- tion of Graduate School of China Three Gorges Univer- sity.
文摘A high-efficient and stereo-specific approach for the preparation of biologically important （E）-2-styryl-tetra- hydrobenzo[d]thiazoles has been developed via TMSC1 promoted direct sp3 C-H alkenylation of 2-methyl-5,6-di- hydrobenzo[d]thiazol-7（4H）-one under metal-free conditions. Seventeen target compounds were synthesized in ex- cellent yields of 82%--98% under the optimal conditions of 300 mol% TMSCI at 110℃ for 2 h, and their chemical structures were elucidated by IR, NMR, ESI-MS, elemental analyses and X-ray crystallography analysis. A plausible mechanism was also proposed, and this method provided a good functional group conversion for the sp3 C-H substrates.
基金the financial support from the National Natural Science Foundation of China(grant nos.91856111,21871288,21690074,and 21821002)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB 20000000).
文摘Herein,we report the first highly enantioselective Ni-catalyzed arylation and alkenylation of simple aldehydes using readily available and stable organoboronic esters.This protocol provides various chiral secondary alcohols in high yields and enantioselectivities(up to 97% ee)with a broad scope of substrates,functional groups,and heterocycles.The use of a bulky N-heterocyclic carbene(NHC)ligand for nickel catalyst is the key to high enantiocontrol.The competitive Ni-catalyzed transformations,including Tishchenko reaction,dehydrogenation/hydrogenation reaction,and Suzuki-Miyaura couplings,are avoided.The excellent chemoselectivity is likely due to the application of mild base CsF and η^(2)-coordination of aldehydes with nickel.
文摘Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to the inevitable side reactions involving cycloaddition.Herein,the visible-light-mediated O-H functionalization reactions of alkenyl alcohols with diazo compounds were developed.This process competed favorably with the cycloaddition reaction.A series of multifunctional ethers were provided in low to high yields with aryldiazoacetates or 3-diazooxindoles.Biologically relevant spirooxindole-fused oxacycle could be easily accessed from the O-H functionalization product of alkenyl alcohol and 3-diazooxindole.
文摘A visible-light-enabled method for the synthesis ofα-azidoketones has been developed via oxo-azidation of alkenyl silanes with trimethylsilylazide and molecular oxygen under mild conditions.The reaction could be carried out in gram scale.Various radical sources,including trifluoromethyl radical,thiocyanate radical,bromide radical,chlorine radical could partici-pate effectively instead of azide radical in the reaction.
基金Financial support from National Natural Science Foundation of China(Nos.21871282,22377113,22301309)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0590000)+6 种基金National Key Research and Development Program of China(No.2023YFA0914502)Taishan Scholar Program of Shandong Province(No.tsqn202306103,tsqn202306026)Postdoctoral Fellowship Program of CPSF(No.GZC20232509)Distinguished Young Scholars of Shandong Province(Overseas)(No.2022HWYQ-004)Shandong Postdoctoral Science Foundation(No.SDBX2023044)Qingdao Postdoctoral Science Foundation(No.QDBSH20230202048)the Fundamental Research Funds for the Central Universities(Ocean University of China)。
文摘Pyrazolidinones,as significant analogs ofβ-lactam antibiotics,have garnered substantial interest for their enantioselective synthesis.Azomethine imines,recognized as valuable building blocks for the construction of these nitrogen-containing compounds,underscore the continuous pursuit of novel building blocks and reaction methodologies within the chemical community.In this paper,we present a cascade cyclization between alkenyl azomethine imines and furan-2(5H)-one to generate chiral coronal polyheterocyclic compounds with high yields and enantioselectivities,catalyzed by dipeptide-derived phosphonium salts.In-vitro biological activity assays highlight the potential of these chiral compounds in drug discovery.Additionally,density functional theory(DFT)calculations elucidate the pivotal role of phosphonium salts,demonstrating their cooperative activations via hydrogen bonding and ion-pairing interactions.
基金We are grateful to the National Natural Science Foundation of China(No.21302064)the Natural Science Foundation of Hubei Province(No.2017CFB690).
文摘Main observation and conclusion A new Rh(Ⅲ)-catalyzed direct C—H alkenylation of 2,3-unsubstitued indoles with alkenyl borates through C—H activation followed by transmetallation was described.This protocol provides an efficient method for the synthesis of terminal C2-alkenylindoles under mild conditions,and also shows broad substrate scope and high functional group tolerance with respect to both components.Furthermore,the C2-alkenylated indole can be easily transformed into carboline derivative,which is an important polycyclic indole moiety in natural products and drug molecules.
基金financially supported by the National Natural Science Foundation of China (Nos. 21972112 and 22225104)China Postdoctoral Science Foundation (Nos. 2022TQ0115 and 2022M711297)。
文摘Chemoselective,living/controlled polymerizations of allyl methacrylate(AMA) and vinyl methacrylate(VMA) with/without methyl methacrylate(MMA) by using the phosphonium ylide/organoaluminum based Lewis pairs(LPs) have been realized.The P-ylide-2/AIMe(BHT)_(2)(Pylide-2=Ph_(3)P=CHMe and BHT=2,6-iBu_(2)-4-MeC_(6)H_(2)O) was demonstrated to be superior by which homopolymers PAMAs(M_(n)=27.6-111.5kg/mol and ■=1.14-1.25) and PVMAs(M_(n)=28.4-78.4 kg/mol and ■=1.12-1.18) and block copolymers PMMA-b-PAMA,PAMA-b-PVMA,PAMA-bPMMA,PMMA-b-PAMA-b-PMMA,PAMA-b-PMMA-b-PAMA,and PAMA-b-PVMA-b-PAMA were synthesized.In the polymerizations,all of the monomers were reacted by the conjugated ester vinyl groups leaving intactly the nonconjugated acryloxy groups.The pendant acryloxy groups attached to the main chain enable further to post-functionalization by the AIBN-induced radical "thiol-ene" reaction using PhCH_(2)SH.The thiolether side group-containing polymers PAMA-SCH_(2)Ph and PAMA-SCH_(2)Ph-b-PMMA-b-PAMA-SCH_(2)Ph were thus prepared.
文摘Cesium carbonate was used as a base to achieve the desulfurization reaction of alkenyl sulfonium salts and phosphine oxides at room temperature,forming C(sp2)—P bonds.This method features simple operation,mild reaction conditions,and good functional group compatibility,offering a straightforward and efficient preparation route for terminal vinyl phosphine oxides.
