Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)...Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)bond construction often rely on expensive and scarce transition metal catalysts,raising concerns about sustainability and environmental impact.To address these challenges,we develop a bifunctional photocatalyst,phloroglucinol carbon quantum dot(PG-CQD).It facilitates catalytic transfer hydrogenation(CTH)with IPA as the hydrogen donor.PG-CQDs exhibit both dehydrogenation and reduction activities,enabling the formation of vicinal diols under mild conditions with visible light irradiation.We propose a CTH mechanism that has been successfully validated through experiments.The catalytic system demonstrates remarkable versatility,enabling the synthesis of various vicinal diols from diverseα-keto ester substrates with good or excellent yields.These findings offer a sustainable synthetic strategy that aligns with green chemistry principles and establish a promising pathway for the development of environmentally benign and energy-efficient organic transformations.展开更多
Sm/TiCl4 system could well integrate the high reactivity of samarium（Ⅱ） and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupl...Sm/TiCl4 system could well integrate the high reactivity of samarium（Ⅱ） and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupling reactions of ketones with esters mediated by metallic samarium （Sm） and a catalytic amount of titanium tetrachloride （TiCl4） were successfully developed. A series of substituted ketones and cyclic β-keto-esters were prepared in moderate to good yields under reflux and neutral conditions.展开更多
The intermolecular coupling of a nitro group with a cyano group mediated by a Sm(Hg) amalgam prepared from metal samarium powder and catalytic mercury dichloride was studied.
The synthesis methods ofα-fluoro-arylketones were well-established through electrophilic/nucleophilic fluorination and transition metal catalyzed cross-coupling.However,due to the site selectivity and substrate restr...The synthesis methods ofα-fluoro-arylketones were well-established through electrophilic/nucleophilic fluorination and transition metal catalyzed cross-coupling.However,due to the site selectivity and substrate restriction,only a few cases have been developed to affordα-alkyl-α-fluoro-alkylketones.Herein,we report a general and efficient method of preparing diverseα-alkyl-α-fluoro-alkylketones via nickelcatalyzed reductive coupling reaction of monofluoroalkyl triflates with low-cost industrial raw material alkyl carboxylic acids.These transformations demonstrate high efficiency,mild conditions,and excellent functional group compatibility.This strategy provides a general and efficient method for the synthesis ofα-alkyl-α-fluoro-alkylketones。展开更多
The reductive coupling reactions of aryl sulfonyl chloride induced by (TiCl4-Zn) reagent affords diaryl disulfide. However, reaction of aryl sulfonyl chloride with α,β-unsaturated ester under the same condition affo...The reductive coupling reactions of aryl sulfonyl chloride induced by (TiCl4-Zn) reagent affords diaryl disulfide. However, reaction of aryl sulfonyl chloride with α,β-unsaturated ester under the same condition affords β-arylsulfo ester.展开更多
Selectivity-control has long been a central pursuit in organic chemistry.Most recent advances have focused on achieving individual forms of selectivity,such as chemo-,regio-,E/Z-,diastereo-,or enantioselectivity.Tradi...Selectivity-control has long been a central pursuit in organic chemistry.Most recent advances have focused on achieving individual forms of selectivity,such as chemo-,regio-,E/Z-,diastereo-,or enantioselectivity.Traditionally,multi-selectivities have been realized through one-dimensional linear synthetic routes,in which distinct sites are modified sequentially across multiple reaction steps.展开更多
Compared with rare and expensive late-transition metals,rare-earth photocatalysts are much less investigated in synthetic chemistry,particularly concerning redox-inactive rare-earth metals.Herein,we describe a general...Compared with rare and expensive late-transition metals,rare-earth photocatalysts are much less investigated in synthetic chemistry,particularly concerning redox-inactive rare-earth metals.Herein,we describe a general strategy to realize the redox-inactive rare-earth photocatalysis by grafting a light-absorbing scaffold onto common ligands in rare-earth organometallics.Three guanidinate rare-earth complexes with photocatalytic functions were synthesized and found to exhibit higher catalytic efficiency than phenothiazine in the reductive homocoupling of benzyl bromides.These preliminary results illustrated that our“grafting”strategy could serve as a facile methodology for the construction of redox-inactive rare-earth photocatalysis systems.展开更多
Nickel-catalyzed reductive cross-coupling(RCC)reactions between alkenes and alkyl electrophiles are undoubtedly the attractive approaches to new functionalized heterocycles.However,the alkylation reagents are still ra...Nickel-catalyzed reductive cross-coupling(RCC)reactions between alkenes and alkyl electrophiles are undoubtedly the attractive approaches to new functionalized heterocycles.However,the alkylation reagents are still rather limited for the arylalkylation of tethered alkenes via RCC reactions.Thus,developing more robust methods to access heterocycles from stable and readily available starting materials under RCC conditions is still highly challenging and desirable.A new nickelcatalyzed reductive arylalkylation of tethered alkenes with cyclosulfonium salts as C(sp^(3))electrophiles to access the sulfurcontaining oxindoles is developed.This tandem ring-opening/cyclization/reductive coupling protocol enables the efficient construction of various oxindoles bearing all-carbon quaternary centers under mild conditions with broad functional group tolerance.Notably,many drug derivatives are readily functionalized using the developed protocol.展开更多
The metal‐reduction‐induced dechlorination coupling(MR-DC)strategy enables the first successful synthesis of an all‐inorganic crosslinked phosphazene network(aPN)from hexachlorocyclotriphosphazene(HCCP)under mild r...The metal‐reduction‐induced dechlorination coupling(MR-DC)strategy enables the first successful synthesis of an all‐inorganic crosslinked phosphazene network(aPN)from hexachlorocyclotriphosphazene(HCCP)under mild reaction conditions.Using Cu as a model,the resulting Cu-aPN(copper‐embedded all‐inorganic phosphazene network)retains the intrinsic N_(3)P_(3)backbone and exhibits an amorphous structure where Cu species are uniformly anchored at dense P/N coordination sites of the network.Time of flight secondary ion mass spectrometry(TOF‐SIMS)and X‐ray diffraction(XRD)reveal a gradual CuCl‐to‐CuO phase conversion during ammonia treatment,which effectively ensures the structural stability of the phosphazene framework.In 1 M KOH,Cu-aPN delivers an overpotential of 280 mV at 10 mA cm^(−2)and a Tafel slope of 48 mV dec^(−1),markedly outperforming Ga-aPN.In situ Raman and density functional theory(DFT)analyses indicate stronger Cu-P/N coordination coupling that lowers the*OH formation barrier(0.39 vs.0.88 eV for Ga).This MR-DC route furnishes a general and versatile pathway for constructing metal‐embedded all‐inorganic phosphazene frameworks with tunable coordination environments for advanced electrocatalytic applications.展开更多
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
Herein we report a method for highly diastereoselective and enantioselective nickel-catalyzed reductive coupling of imines and unactivated alkenes.A monodentate chiral spiro phosphoramidite ligand is the key to contro...Herein we report a method for highly diastereoselective and enantioselective nickel-catalyzed reductive coupling of imines and unactivated alkenes.A monodentate chiral spiro phosphoramidite ligand is the key to controlling the enantioselectivity.This efficient,straightforward method allows for the construction of chiral benzocyclic and indole-fused cyclic amines with two contiguous stereogenic centers in good yields from readily accessible starting materials.展开更多
The intermolecular reductive coupling cyclization reactions of 1,1-dicyanoalkenes promoted by Sm-0/cat. HgCl2 were studied. A possible reaction mechanism was proposed.
Herein,we report a borane-promoted reductive deoxygenation coupling reaction to synthesize sulfides.This reaction features excellent functional group compatibility,high efficiency,broad substrate scope,and application...Herein,we report a borane-promoted reductive deoxygenation coupling reaction to synthesize sulfides.This reaction features excellent functional group compatibility,high efficiency,broad substrate scope,and application in late-stage functionalization of biomolecules.Preliminary mechanistic studies suggest diaryl sulfides are the intermediates of this reaction.Moreover,the real active aryl sulfide anions may be generated in situ with the aid of B2pin2 and react with alkyl tosylates through a concerted SN2 pathway.展开更多
A new cooperative nickel reductive catalysis and N,N-dimethylformamide-mediated strategy for umpolung C–S radical reductive cross coupling of S-(trifluoromethyl)arylsulfonothioates with alkyl halides to produce alkyl...A new cooperative nickel reductive catalysis and N,N-dimethylformamide-mediated strategy for umpolung C–S radical reductive cross coupling of S-(trifluoromethyl)arylsulfonothioates with alkyl halides to produce alkyl aryl thioethers is described. This reaction features excellent selectivity, wide functionality tolerance, broad substrate scope, and facile late-stage modification of biologically relevant molecules.Mechanistic studies recognize initial generation of an amidyl radical anion via thermoinduced reduction of DMF with Sn, followed by umpolung reduction and single electron transfer of the nucleophilic sulfonyl moiety to form a sulphydryl radical and engage the Ni^(0)/Ni^(Ⅰ)/Ni^(Ⅲ)/Ni^(I) catalytic cycle.展开更多
Light-driven CO_(2) reduction reaction(CO_(2)RR)to value-added ethylene(C2H4)holds significant promise for addressing energy and environmental challenges.While the high energy barriers for*CO intermediates hydrogenati...Light-driven CO_(2) reduction reaction(CO_(2)RR)to value-added ethylene(C2H4)holds significant promise for addressing energy and environmental challenges.While the high energy barriers for*CO intermediates hydrogenation and C–C coupling limit the C_(2)H_(4)generation.Herein,CuxP/g-C_(3)N_(4) heterojunction prepared by an in-situ phosphating technique,achieved collaborative photocatalytic CO_(2) and H2O,producing CO and C_(2)H_(4)as the main products.Notably,the selectivity of C_(2)H_(4)produced by CuxP/g-C_(3)N_(4) attained to 64.25%,which was 9.85 times that of CuxP(6.52%).Detailed time-resolution photoluminescence spectra,femtosecond transient absorption spectroscopy tests and density functional theory(DFT)calculation validate the ultra-fast interfacial electron transfer mechanism in CuxP/g-C_(3)N_(4) heterojunction.Successive*H on P sites caused by adsorbed H2O splitting with moderate hydrogenation ability enables the multi-step hydrogenation during CO_(2)RR process over CuxP/g-C_(3)N_(4).With the aid of mediated asymmetric Cu and P dual sites by g-C_(3)N_(4) nanosheet,the produced*CHO shows an energetically favorable for C–C coupling.The coupling formed*CHOCHO further accepts photoexcited efficient e–and*H to deeply produce C_(2)H_(4)according to the C^(2+)intermediates,which has been detected by in-situ diffuse reflectance infrared Fourier transform spectroscopy and interpreted by DFT calculation.The novel insight mechanism offers an essential understanding for the development of CuxP-based heterojunctions for photocatalytic CO_(2) to C^(2+)value-added fuels.展开更多
Aromatic aldehydes are the most fundamentally important compounds used in organic synthesis.The development of new synthetic methods for introduction of a formyl group into an organic scaffold is highly desirable.In t...Aromatic aldehydes are the most fundamentally important compounds used in organic synthesis.The development of new synthetic methods for introduction of a formyl group into an organic scaffold is highly desirable.In this report,a nickel-catalyzed reductive coupling between aryl halides andα–chloro N-methoxyphthalimide has been documented for the synthesis of a diverse array of aromatic aldehydes.Because of mild reductive coupling conditions,excellent functional group tolerance,especially for substrates containing free-OH and-NH_(2),was observed.Due to the simple operation mode,a large library of aromatic aldehydes can be quickly constructed by this process.Moreover,the present protocol is amenable for late-stage functionalization of bioactive compound.A combined computational and experimental investigation suggested the reaction may undergo a reaction mechanism of active Ni(I)catalyst formation and the formation of key formyl radical intermediate under zinc reductive conditions.展开更多
In this paper, an ultra-compact single negative（SNG） electric waveguided metamaterial（WG-MTM） is first investigated and used to reduce the mutual coupling in E ＆ H planes of a dual-band microstrip antenna array. ...In this paper, an ultra-compact single negative（SNG） electric waveguided metamaterial（WG-MTM） is first investigated and used to reduce the mutual coupling in E ＆ H planes of a dual-band microstrip antenna array. The proposed SNG electric WG-MTM unit cell is designed by etching two different symmetrical spiral lines on the ground, and has two stopbands operating at 1.86 GHz and 2.40 GHz. The circuit size is very compact, which is only λ_0/33.6 ×λ_0/15.1（where λ_0 is the wavelength at 1.86 GHz in free space）. Taking advantage of the dual-stopband property of the proposed SNG electric WG-MTM, a dual-band microstrip antenna array operating at 1.86 GHz and 2.40 GHz with very low mutual coupling is designed by embedding a cross shaped array of the proposed SNG electric WG-MTM. The measured and simulated results of the designed dual-band antenna array are in good agreement with each other, indicating that the mutual coupling of the fabricated dual-band antenna array realizes 9.8/11.1 d B reductions in the H plane, 8.5/7.9 d B reductions in the E plane at1.86 GHz and 2.40 GHz, respectively. Besides, the distance of the antenna elements in the array is only 0.35 λ_0（where λ_0 is the wavelength at 1.86 GHz in free space）. The proposed strategy is used for the first time to reduce the mutual coupling in E ＆ H planes of the dual-band microstrip antenna array by using ultra-compact SNG electric WG-MTM.展开更多
While the reductive coupling of two nitriles mediated by transition metals has been widely studied in the past ten years,the analogous process promoted by rare-earth metals remains elusive.Herein,we report the selecti...While the reductive coupling of two nitriles mediated by transition metals has been widely studied in the past ten years,the analogous process promoted by rare-earth metals remains elusive.Herein,we report the selective C–C coupling of two nitriles by rare-earth metal reduced naphthalene complexes to assem-ble the first authentic rare-earth diazametallacyclopentadienes.Mechanistic studies reveal that the reac-tion proceeds through the insertion–release–insertion sequence,which is different from the known oxi-dative cyclometallation process for transition metals.This provides an alternative mechanism for metal-mediated reductive coupling of two nitriles.Furthermore,reactivity investigation indicates that diazascan-dacyclopentadiene exhibits distinct 1,4-hydrogenation and insertion reactions toward H_(2),isothiocyanate,isocyanide,and W(CO)_(6) to give diversified rare-earth metallacycles.These results indicate that rare-earth diazametallacyclopentadienes present unique chemistry,which is different from that of group 4 diazametallacyclopentadienes.展开更多
A new strategy for tuning rare-earth hydride reactivity has been developed using a reductive ligand.The reaction of diazabutadienyl-supported rare-earth hydride[(DAD)Y·THF]_(2)(μ-H)_(2)(DAD=N,N’-di(2,6-diisopro...A new strategy for tuning rare-earth hydride reactivity has been developed using a reductive ligand.The reaction of diazabutadienyl-supported rare-earth hydride[(DAD)Y·THF]_(2)(μ-H)_(2)(DAD=N,N’-di(2,6-diisopropylphenyl)-1,4-diazabutadienyl dianion),(1)with two equiv.of Ph_(2)CO gave a reduced Ph_(2)CO-coupled product(DAD’Y)_(2)(μ-H)_(2)(μ-η^(2):η^(1)-Ph_(2)C(O)C(O)Ph_(2))(THF)(DAD’=N,N’-di(2,6-diisopropylphenyl)-1,4-diazabutadienyl radical-anion,2),in which active Y-H bonds were retained,while 1 reacted with PhC(O)Cy to yield a Y-H bond insertion product[(DAD)Y(μ-OC(H)PhCy)]_(2)(3).Complex 3 further reacted with PhC(O)Cy and lithium metal to give a C-C coupled product(DAD’)Y(PhCyC(O)C(O)PhCy)(OC(H)PhCy)Li(THF)(4).An investigation of the scope of reactivity of 1 found it reacted with PhNvNPh to produce a two-electron reduced product(DAD’Y)_(2)(μ-N(Ph)NPh)_(2)(THF)(5),accompanied by the elimination of H2.The reaction of 1 with acridine afforded two structurally characterized yttrium 9-H acridinyl complexes(DAD)Y(NC_(13)H_(10))(THF)_(2)(6)and(DAD’)Y(NC_(13)H_(10))_(2)(THF)(7).Investigations into the reactivity of 2 showed that 2 facilely reacted with PhCuCH to give an unusual hydride H−and radical-anionic DAD ligand coupled product(DAD)Y(μ-Ph_(2)C(O)C(O)Ph_(2))(μ-η^(2):η^(1)-CuCPh)Y(HDAD)(8),while 2 reacted with Me_(3)SiCuCH to afford the mono Me_(3)SiCuCH protolysis product(DAD’)Y(μ-Ph_(2)C(O)C(O)Ph_(2))(CuCSiMe_(3))(μ-H)Y(DAD’)(9),in which no hydride H−migration occurred.These results indicated that the electronic properties of the reductive DAD ligand strongly modified the reactivity of rare-earth hydrides.展开更多
基金National Natural Science Foundation of China(Nos.21902023 and 21901252)Shanghai Pujiang Program,China(No.19PJ1400300)+1 种基金Professor of Special Appointment(Eastern Scholar),ChinaShanghai Institutions of Higher Education Fundamental Research Funds for the Central Universities,China(No.0900000155)。
文摘Catalytic reduction reactions using isopropanol(IPA)as a transfer hydrogenating agent are gaining significant attention due to the low cost and large-scale production of IPA.Traditional methods for carbon-carbon(C—C)bond construction often rely on expensive and scarce transition metal catalysts,raising concerns about sustainability and environmental impact.To address these challenges,we develop a bifunctional photocatalyst,phloroglucinol carbon quantum dot(PG-CQD).It facilitates catalytic transfer hydrogenation(CTH)with IPA as the hydrogen donor.PG-CQDs exhibit both dehydrogenation and reduction activities,enabling the formation of vicinal diols under mild conditions with visible light irradiation.We propose a CTH mechanism that has been successfully validated through experiments.The catalytic system demonstrates remarkable versatility,enabling the synthesis of various vicinal diols from diverseα-keto ester substrates with good or excellent yields.These findings offer a sustainable synthetic strategy that aligns with green chemistry principles and establish a promising pathway for the development of environmentally benign and energy-efficient organic transformations.
基金Project (No. 2004C21032) supported by the Key Technologies R &D Program of Zhejiang Province, China
文摘Sm/TiCl4 system could well integrate the high reactivity of samarium（Ⅱ） and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupling reactions of ketones with esters mediated by metallic samarium （Sm） and a catalytic amount of titanium tetrachloride （TiCl4） were successfully developed. A series of substituted ketones and cyclic β-keto-esters were prepared in moderate to good yields under reflux and neutral conditions.
基金National Natural Science Foundation of China (Project No. 20072033) and Natural Science Foundation of Zhejiang province for financial support.
文摘The intermolecular coupling of a nitro group with a cyano group mediated by a Sm(Hg) amalgam prepared from metal samarium powder and catalytic mercury dichloride was studied.
基金the financial support of the National Key R&D Program of China(No.2021YFF0701700)the National Science Foundation of China(Nos.22271264,21971228)。
文摘The synthesis methods ofα-fluoro-arylketones were well-established through electrophilic/nucleophilic fluorination and transition metal catalyzed cross-coupling.However,due to the site selectivity and substrate restriction,only a few cases have been developed to affordα-alkyl-α-fluoro-alkylketones.Herein,we report a general and efficient method of preparing diverseα-alkyl-α-fluoro-alkylketones via nickelcatalyzed reductive coupling reaction of monofluoroalkyl triflates with low-cost industrial raw material alkyl carboxylic acids.These transformations demonstrate high efficiency,mild conditions,and excellent functional group compatibility.This strategy provides a general and efficient method for the synthesis ofα-alkyl-α-fluoro-alkylketones。
文摘The reductive coupling reactions of aryl sulfonyl chloride induced by (TiCl4-Zn) reagent affords diaryl disulfide. However, reaction of aryl sulfonyl chloride with α,β-unsaturated ester under the same condition affords β-arylsulfo ester.
文摘Selectivity-control has long been a central pursuit in organic chemistry.Most recent advances have focused on achieving individual forms of selectivity,such as chemo-,regio-,E/Z-,diastereo-,or enantioselectivity.Traditionally,multi-selectivities have been realized through one-dimensional linear synthetic routes,in which distinct sites are modified sequentially across multiple reaction steps.
基金supported by the National Key R&D Program of China(No.2021YFF0701600)the National Natural Science Foundation of China(Nos.22371006 and 22271001).
文摘Compared with rare and expensive late-transition metals,rare-earth photocatalysts are much less investigated in synthetic chemistry,particularly concerning redox-inactive rare-earth metals.Herein,we describe a general strategy to realize the redox-inactive rare-earth photocatalysis by grafting a light-absorbing scaffold onto common ligands in rare-earth organometallics.Three guanidinate rare-earth complexes with photocatalytic functions were synthesized and found to exhibit higher catalytic efficiency than phenothiazine in the reductive homocoupling of benzyl bromides.These preliminary results illustrated that our“grafting”strategy could serve as a facile methodology for the construction of redox-inactive rare-earth photocatalysis systems.
基金Project supported by the National Natural Science Foundation of China(No.22271170)the Taishan Scholars Program from Shandong Province(No.tsqn202408197)the Natural Science Foundation of Shandong Province(No.ZR2024QB154)。
文摘Nickel-catalyzed reductive cross-coupling(RCC)reactions between alkenes and alkyl electrophiles are undoubtedly the attractive approaches to new functionalized heterocycles.However,the alkylation reagents are still rather limited for the arylalkylation of tethered alkenes via RCC reactions.Thus,developing more robust methods to access heterocycles from stable and readily available starting materials under RCC conditions is still highly challenging and desirable.A new nickelcatalyzed reductive arylalkylation of tethered alkenes with cyclosulfonium salts as C(sp^(3))electrophiles to access the sulfurcontaining oxindoles is developed.This tandem ring-opening/cyclization/reductive coupling protocol enables the efficient construction of various oxindoles bearing all-carbon quaternary centers under mild conditions with broad functional group tolerance.Notably,many drug derivatives are readily functionalized using the developed protocol.
基金financially supported by the National Natural Science Foundation of China(Grant 22205173)the Innovation Capability Support Program of Shaanxi(Grant 2024CX‐GXPT‐12)。
文摘The metal‐reduction‐induced dechlorination coupling(MR-DC)strategy enables the first successful synthesis of an all‐inorganic crosslinked phosphazene network(aPN)from hexachlorocyclotriphosphazene(HCCP)under mild reaction conditions.Using Cu as a model,the resulting Cu-aPN(copper‐embedded all‐inorganic phosphazene network)retains the intrinsic N_(3)P_(3)backbone and exhibits an amorphous structure where Cu species are uniformly anchored at dense P/N coordination sites of the network.Time of flight secondary ion mass spectrometry(TOF‐SIMS)and X‐ray diffraction(XRD)reveal a gradual CuCl‐to‐CuO phase conversion during ammonia treatment,which effectively ensures the structural stability of the phosphazene framework.In 1 M KOH,Cu-aPN delivers an overpotential of 280 mV at 10 mA cm^(−2)and a Tafel slope of 48 mV dec^(−1),markedly outperforming Ga-aPN.In situ Raman and density functional theory(DFT)analyses indicate stronger Cu-P/N coordination coupling that lowers the*OH formation barrier(0.39 vs.0.88 eV for Ga).This MR-DC route furnishes a general and versatile pathway for constructing metal‐embedded all‐inorganic phosphazene frameworks with tunable coordination environments for advanced electrocatalytic applications.
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 National Natural Science Foundation of China(Nos.21790332,91956000,22188101)the Fundamental Research Funds for the Central Universities,and the Haihe Laboratory of Sustainable Chemical Transformations for their financial support.
文摘Herein we report a method for highly diastereoselective and enantioselective nickel-catalyzed reductive coupling of imines and unactivated alkenes.A monodentate chiral spiro phosphoramidite ligand is the key to controlling the enantioselectivity.This efficient,straightforward method allows for the construction of chiral benzocyclic and indole-fused cyclic amines with two contiguous stereogenic centers in good yields from readily accessible starting materials.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 0 0 72 0 33)andtheNaturalScienceFoundationofZhejiangProvince (No .2 980 6 7) .
文摘The intermolecular reductive coupling cyclization reactions of 1,1-dicyanoalkenes promoted by Sm-0/cat. HgCl2 were studied. A possible reaction mechanism was proposed.
基金support from Natural Science Foundation of Sichuan(No.2021YJ0413)Sichuan Key Laboratory of Medical Imaging(North Sichuan Medical College,No.SKLMI201901)+2 种基金Strategic Cooperation of Science and Technology between Nanchong City and North Sichuan Medical College(Nos.19SXHZ0441,19SXHZ0227)Chongqing Postdoctoral Science Foundation(No.cstc2020jcyj-bshX0052)China Postdoctoral Science Foundation(No.2020M673121).
文摘Herein,we report a borane-promoted reductive deoxygenation coupling reaction to synthesize sulfides.This reaction features excellent functional group compatibility,high efficiency,broad substrate scope,and application in late-stage functionalization of biomolecules.Preliminary mechanistic studies suggest diaryl sulfides are the intermediates of this reaction.Moreover,the real active aryl sulfide anions may be generated in situ with the aid of B2pin2 and react with alkyl tosylates through a concerted SN2 pathway.
基金the National Natural Science Foundation of China(No.22271245)the Jiangxi Province Science and Technology Project(Nos.20212AEI91002 and 20202ACBL213002)the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University(No.2021ZD01)for financial support.
文摘A new cooperative nickel reductive catalysis and N,N-dimethylformamide-mediated strategy for umpolung C–S radical reductive cross coupling of S-(trifluoromethyl)arylsulfonothioates with alkyl halides to produce alkyl aryl thioethers is described. This reaction features excellent selectivity, wide functionality tolerance, broad substrate scope, and facile late-stage modification of biologically relevant molecules.Mechanistic studies recognize initial generation of an amidyl radical anion via thermoinduced reduction of DMF with Sn, followed by umpolung reduction and single electron transfer of the nucleophilic sulfonyl moiety to form a sulphydryl radical and engage the Ni^(0)/Ni^(Ⅰ)/Ni^(Ⅲ)/Ni^(I) catalytic cycle.
文摘Light-driven CO_(2) reduction reaction(CO_(2)RR)to value-added ethylene(C2H4)holds significant promise for addressing energy and environmental challenges.While the high energy barriers for*CO intermediates hydrogenation and C–C coupling limit the C_(2)H_(4)generation.Herein,CuxP/g-C_(3)N_(4) heterojunction prepared by an in-situ phosphating technique,achieved collaborative photocatalytic CO_(2) and H2O,producing CO and C_(2)H_(4)as the main products.Notably,the selectivity of C_(2)H_(4)produced by CuxP/g-C_(3)N_(4) attained to 64.25%,which was 9.85 times that of CuxP(6.52%).Detailed time-resolution photoluminescence spectra,femtosecond transient absorption spectroscopy tests and density functional theory(DFT)calculation validate the ultra-fast interfacial electron transfer mechanism in CuxP/g-C_(3)N_(4) heterojunction.Successive*H on P sites caused by adsorbed H2O splitting with moderate hydrogenation ability enables the multi-step hydrogenation during CO_(2)RR process over CuxP/g-C_(3)N_(4).With the aid of mediated asymmetric Cu and P dual sites by g-C_(3)N_(4) nanosheet,the produced*CHO shows an energetically favorable for C–C coupling.The coupling formed*CHOCHO further accepts photoexcited efficient e–and*H to deeply produce C_(2)H_(4)according to the C^(2+)intermediates,which has been detected by in-situ diffuse reflectance infrared Fourier transform spectroscopy and interpreted by DFT calculation.The novel insight mechanism offers an essential understanding for the development of CuxP-based heterojunctions for photocatalytic CO_(2) to C^(2+)value-added fuels.
基金financial support from the National Natural Science Foundation of China(No.22001147)Taishan Scholars Project of Shandong Province(No.tsqn202103027)+1 种基金Distinguished Young Scholars of Shandong Province(Overseas)(No.2022HWYQ-001)Qilu Youth Scholar Funding of Shandong University。
文摘Aromatic aldehydes are the most fundamentally important compounds used in organic synthesis.The development of new synthetic methods for introduction of a formyl group into an organic scaffold is highly desirable.In this report,a nickel-catalyzed reductive coupling between aryl halides andα–chloro N-methoxyphthalimide has been documented for the synthesis of a diverse array of aromatic aldehydes.Because of mild reductive coupling conditions,excellent functional group tolerance,especially for substrates containing free-OH and-NH_(2),was observed.Due to the simple operation mode,a large library of aromatic aldehydes can be quickly constructed by this process.Moreover,the present protocol is amenable for late-stage functionalization of bioactive compound.A combined computational and experimental investigation suggested the reaction may undergo a reaction mechanism of active Ni(I)catalyst formation and the formation of key formyl radical intermediate under zinc reductive conditions.
基金Project supported by the National Natural Science Foundation of China(Grant No.61372034)
文摘In this paper, an ultra-compact single negative（SNG） electric waveguided metamaterial（WG-MTM） is first investigated and used to reduce the mutual coupling in E ＆ H planes of a dual-band microstrip antenna array. The proposed SNG electric WG-MTM unit cell is designed by etching two different symmetrical spiral lines on the ground, and has two stopbands operating at 1.86 GHz and 2.40 GHz. The circuit size is very compact, which is only λ_0/33.6 ×λ_0/15.1（where λ_0 is the wavelength at 1.86 GHz in free space）. Taking advantage of the dual-stopband property of the proposed SNG electric WG-MTM, a dual-band microstrip antenna array operating at 1.86 GHz and 2.40 GHz with very low mutual coupling is designed by embedding a cross shaped array of the proposed SNG electric WG-MTM. The measured and simulated results of the designed dual-band antenna array are in good agreement with each other, indicating that the mutual coupling of the fabricated dual-band antenna array realizes 9.8/11.1 d B reductions in the H plane, 8.5/7.9 d B reductions in the E plane at1.86 GHz and 2.40 GHz, respectively. Besides, the distance of the antenna elements in the array is only 0.35 λ_0（where λ_0 is the wavelength at 1.86 GHz in free space）. The proposed strategy is used for the first time to reduce the mutual coupling in E ＆ H planes of the dual-band microstrip antenna array by using ultra-compact SNG electric WG-MTM.
基金supported by the National Key R&D Program of China(no.2021YFF0701600)the National Natural Science Foundation of China(no.21890721,22131001).
文摘While the reductive coupling of two nitriles mediated by transition metals has been widely studied in the past ten years,the analogous process promoted by rare-earth metals remains elusive.Herein,we report the selective C–C coupling of two nitriles by rare-earth metal reduced naphthalene complexes to assem-ble the first authentic rare-earth diazametallacyclopentadienes.Mechanistic studies reveal that the reac-tion proceeds through the insertion–release–insertion sequence,which is different from the known oxi-dative cyclometallation process for transition metals.This provides an alternative mechanism for metal-mediated reductive coupling of two nitriles.Furthermore,reactivity investigation indicates that diazascan-dacyclopentadiene exhibits distinct 1,4-hydrogenation and insertion reactions toward H_(2),isothiocyanate,isocyanide,and W(CO)_(6) to give diversified rare-earth metallacycles.These results indicate that rare-earth diazametallacyclopentadienes present unique chemistry,which is different from that of group 4 diazametallacyclopentadienes.
基金the National Natural Science Foundation of China(Grant No.21871058,22271051,and 22371049)for financial support.
文摘A new strategy for tuning rare-earth hydride reactivity has been developed using a reductive ligand.The reaction of diazabutadienyl-supported rare-earth hydride[(DAD)Y·THF]_(2)(μ-H)_(2)(DAD=N,N’-di(2,6-diisopropylphenyl)-1,4-diazabutadienyl dianion),(1)with two equiv.of Ph_(2)CO gave a reduced Ph_(2)CO-coupled product(DAD’Y)_(2)(μ-H)_(2)(μ-η^(2):η^(1)-Ph_(2)C(O)C(O)Ph_(2))(THF)(DAD’=N,N’-di(2,6-diisopropylphenyl)-1,4-diazabutadienyl radical-anion,2),in which active Y-H bonds were retained,while 1 reacted with PhC(O)Cy to yield a Y-H bond insertion product[(DAD)Y(μ-OC(H)PhCy)]_(2)(3).Complex 3 further reacted with PhC(O)Cy and lithium metal to give a C-C coupled product(DAD’)Y(PhCyC(O)C(O)PhCy)(OC(H)PhCy)Li(THF)(4).An investigation of the scope of reactivity of 1 found it reacted with PhNvNPh to produce a two-electron reduced product(DAD’Y)_(2)(μ-N(Ph)NPh)_(2)(THF)(5),accompanied by the elimination of H2.The reaction of 1 with acridine afforded two structurally characterized yttrium 9-H acridinyl complexes(DAD)Y(NC_(13)H_(10))(THF)_(2)(6)and(DAD’)Y(NC_(13)H_(10))_(2)(THF)(7).Investigations into the reactivity of 2 showed that 2 facilely reacted with PhCuCH to give an unusual hydride H−and radical-anionic DAD ligand coupled product(DAD)Y(μ-Ph_(2)C(O)C(O)Ph_(2))(μ-η^(2):η^(1)-CuCPh)Y(HDAD)(8),while 2 reacted with Me_(3)SiCuCH to afford the mono Me_(3)SiCuCH protolysis product(DAD’)Y(μ-Ph_(2)C(O)C(O)Ph_(2))(CuCSiMe_(3))(μ-H)Y(DAD’)(9),in which no hydride H−migration occurred.These results indicated that the electronic properties of the reductive DAD ligand strongly modified the reactivity of rare-earth hydrides.
