Terminal monohaloalkenes are common synthetic fragments used in organic synthesis and are also found in many natural products.Their Z/E stereoisomers are difficult to physically separate,being a persistent difficulty ...Terminal monohaloalkenes are common synthetic fragments used in organic synthesis and are also found in many natural products.Their Z/E stereoisomers are difficult to physically separate,being a persistent difficulty for functional molecular design and synthesis.Herein,we report complementary hydride and hydrogen radical generation pathways to effectuate hydrodehalogenation and deuterodehalogenation of gem-dihaloalkenes,producing stereo-defined deuterated or nondeuterated(Z)-and(E)-terminal monofluoroalkenes and(E)-terminal monochloroalkenes.Our methods have broad substrate scopes and good functional group tolerance.Mechanistic studies and density functional theory calculations elucidate the stereoselectivity.展开更多
Herein,we describe a direct route for the synthesis of 3-gem-difluorovinyl lactams through Zn-mediated reductive hydrodehalogenation.Importantly,by using inexpensive deuterium oxide(D_(2)O),the high value-added vicina...Herein,we describe a direct route for the synthesis of 3-gem-difluorovinyl lactams through Zn-mediated reductive hydrodehalogenation.Importantly,by using inexpensive deuterium oxide(D_(2)O),the high value-added vicinal dideuterated gem-difluoroalkenes with excellent deuterium(D)incorporation were prepared.Mechanism studies indicated a successive single electron transfer process:the reaction initially undergoes hydrodechlorination to give the intermediateα-trifluoromethylidene lactams,which are then activated by the in-situ generated zinc cations and reduced to the desired product via hydrodefluorination.展开更多
Tuning the electronic properties of single atom catalysts(SACs)between the central metal and the neighboring surface atoms has emerged as an efficient strategy to boost catalytic efficiency and metal utilization.Here ...Tuning the electronic properties of single atom catalysts(SACs)between the central metal and the neighboring surface atoms has emerged as an efficient strategy to boost catalytic efficiency and metal utilization.Here we describe a simple and efficient approach to create atomically dispersed palladium atoms supported over defect-containing porous ceria nanorod containing palladium up to 0.26 wt.%.The existence of singly dispersed palladium atoms is confirmed by spherical aberration correction electron microscopy and extended X-ray absorption fine structure measurements.This catalyst shows excellent efficiency in hydrodehalogenation reactions at low H2 pressure under mild conditions,along with satisfactory recyclability and scalability.Density functional theory(DFT)calculations reveal that the high activity stems from the spatial isolation of palladium atoms and the modified electronic structure of palladium confined in defect-containing ceria nanorod.This work may lay the foundation for the facile creation of single atom catalysts within the synthetic community and shed light on the possibility for scale-up production.展开更多
THE reduction of organic halides to the corresponding hydrocarbons plays an important role inorganic synthesis and environmental decontamination.It is one of the earliest reactions de-scribed in the organic chemical l...THE reduction of organic halides to the corresponding hydrocarbons plays an important role inorganic synthesis and environmental decontamination.It is one of the earliest reactions de-scribed in the organic chemical literature.A number of successful approaches have been report-ed hitherto,but the hydrodehalogenation of chloroarenes and organic fluorides is still a展开更多
Ligand modification of Ni-based catalysts by coordination of dicyandiamide to Ni metal leads to enhanced selectivity for the selective hydrogenation of halonitroaromatics.The selectivity of above 99.9%to aromatic halo...Ligand modification of Ni-based catalysts by coordination of dicyandiamide to Ni metal leads to enhanced selectivity for the selective hydrogenation of halonitroaromatics.The selectivity of above 99.9%to aromatic haloamines can be achieved at the conversion of 100%.The results of H_2-TPD and FT-IR experiments show that Ni^-H~＋ species possessing the properties of Lewis acid site on the surface of Raney Ni could be responsible for the hydrodehalogenation.When Raney Ni was treated by dicyandiamide,Ni^-H~＋ species interacted with N atom from the dicyandiamide.This interaction was stable even at reaction temperature,which reduced the possibility to form the intermediate state of Ar-Cl...H~＋Ni^-.And then C-Cl bond could not be polarized and activated.The hvdrodechlorination process was suppressed effectively.展开更多
Polyurea-entrapped palladium nanoclusters have been prepared by interfacial polymerization in W/O emulsion and showed high thermal stability and chemical stability with the content of 0.12 mmol g-1 Pd.This catalyst ex...Polyurea-entrapped palladium nanoclusters have been prepared by interfacial polymerization in W/O emulsion and showed high thermal stability and chemical stability with the content of 0.12 mmol g-1 Pd.This catalyst exhibited dual catalytic activity for reduction of nitro compounds and hydrodehalogenation of aromatic chlorides in atmospheric hydrogen with 100% yield for reduction of nitro compounds and 】99% yield for hydrodehalogenation of aromatic chlorides.This immobilizing method was particularly effective and eliminated the need of special chelating groups.展开更多
Iron-catalyzed direct reduction of allylic halides with benzylic alcohol was achieved,providing a new,simple,and efficient method for conducting highly regioselective hydrodehalogenation.This method not only features ...Iron-catalyzed direct reduction of allylic halides with benzylic alcohol was achieved,providing a new,simple,and efficient method for conducting highly regioselective hydrodehalogenation.This method not only features a readily available reductant,an inexpensive catalyst,simple manipulation,and good tolerance of functional groups including nitriles,nitro,esters,and methoxyl groups,it also has mild reaction conditions and shows complete regioselectivity in that only halides sited at the allylic position are reduced.Alternatively,this method can be applied in the selective transformation of benzylic alcohols to aromatic aldehydes without overoxidation to carboxylic acids.展开更多
基金support from the National Natural Science Foundation of China(grant nos.22293011 and 22371273)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(grant no.2023476)+1 种基金the National Science Foundation of Anhui Province(grant no.2208085J26)the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘Terminal monohaloalkenes are common synthetic fragments used in organic synthesis and are also found in many natural products.Their Z/E stereoisomers are difficult to physically separate,being a persistent difficulty for functional molecular design and synthesis.Herein,we report complementary hydride and hydrogen radical generation pathways to effectuate hydrodehalogenation and deuterodehalogenation of gem-dihaloalkenes,producing stereo-defined deuterated or nondeuterated(Z)-and(E)-terminal monofluoroalkenes and(E)-terminal monochloroalkenes.Our methods have broad substrate scopes and good functional group tolerance.Mechanistic studies and density functional theory calculations elucidate the stereoselectivity.
基金the Guangdong Basic and Applied Basic Research Foundation(2023A1515012657,2024A1515012128)Scientific Research Project of General Universities in Guangdong Province(2022KTSCX046)+3 种基金Zhanjiang Ocean Young Talent Innovation Project(2023E0002,2022E05008)the Fifth-level Research Fund of Guangdong Medical University(4RS23002a,4SG24248G)the Third-level Research Fund of Guangdong Medical University(4RS23002d,4SG22247G)Songshan Lake Medical and Engineering Integration Innovation Project of Guangdong Medical University(4SG22308P)for support.
文摘Herein,we describe a direct route for the synthesis of 3-gem-difluorovinyl lactams through Zn-mediated reductive hydrodehalogenation.Importantly,by using inexpensive deuterium oxide(D_(2)O),the high value-added vicinal dideuterated gem-difluoroalkenes with excellent deuterium(D)incorporation were prepared.Mechanism studies indicated a successive single electron transfer process:the reaction initially undergoes hydrodechlorination to give the intermediateα-trifluoromethylidene lactams,which are then activated by the in-situ generated zinc cations and reduced to the desired product via hydrodefluorination.
基金the China Postdoctoral Science Foundation(Nos.2019M661247 and 2020T130091)Postdoctoral Science Foundation of Heilongjiang Province(No.LBH-Z19047)+1 种基金Program for Overseas Talents Introduction of Northeast Petroleum University(No.15041260303)Scientific Research Foundation for Returned Scholars of Heilongjiang Province of China(No.719900091).
文摘Tuning the electronic properties of single atom catalysts(SACs)between the central metal and the neighboring surface atoms has emerged as an efficient strategy to boost catalytic efficiency and metal utilization.Here we describe a simple and efficient approach to create atomically dispersed palladium atoms supported over defect-containing porous ceria nanorod containing palladium up to 0.26 wt.%.The existence of singly dispersed palladium atoms is confirmed by spherical aberration correction electron microscopy and extended X-ray absorption fine structure measurements.This catalyst shows excellent efficiency in hydrodehalogenation reactions at low H2 pressure under mild conditions,along with satisfactory recyclability and scalability.Density functional theory(DFT)calculations reveal that the high activity stems from the spatial isolation of palladium atoms and the modified electronic structure of palladium confined in defect-containing ceria nanorod.This work may lay the foundation for the facile creation of single atom catalysts within the synthetic community and shed light on the possibility for scale-up production.
文摘THE reduction of organic halides to the corresponding hydrocarbons plays an important role inorganic synthesis and environmental decontamination.It is one of the earliest reactions de-scribed in the organic chemical literature.A number of successful approaches have been report-ed hitherto,but the hydrodehalogenation of chloroarenes and organic fluorides is still a
基金the National Basic Research Program of China(973 Program)(No 2011CB710800)the National Natural Science Foundation of China(No20976164)
文摘Ligand modification of Ni-based catalysts by coordination of dicyandiamide to Ni metal leads to enhanced selectivity for the selective hydrogenation of halonitroaromatics.The selectivity of above 99.9%to aromatic haloamines can be achieved at the conversion of 100%.The results of H_2-TPD and FT-IR experiments show that Ni^-H~＋ species possessing the properties of Lewis acid site on the surface of Raney Ni could be responsible for the hydrodehalogenation.When Raney Ni was treated by dicyandiamide,Ni^-H~＋ species interacted with N atom from the dicyandiamide.This interaction was stable even at reaction temperature,which reduced the possibility to form the intermediate state of Ar-Cl...H~＋Ni^-.And then C-Cl bond could not be polarized and activated.The hvdrodechlorination process was suppressed effectively.
基金supported by the National Natural Science Foundation of China (20976203)the Fundamental Research Funds for the Central Universities
文摘Polyurea-entrapped palladium nanoclusters have been prepared by interfacial polymerization in W/O emulsion and showed high thermal stability and chemical stability with the content of 0.12 mmol g-1 Pd.This catalyst exhibited dual catalytic activity for reduction of nitro compounds and hydrodehalogenation of aromatic chlorides in atmospheric hydrogen with 100% yield for reduction of nitro compounds and 】99% yield for hydrodehalogenation of aromatic chlorides.This immobilizing method was particularly effective and eliminated the need of special chelating groups.
基金the National Natural Science Foundation of China(21132002&21272038)the National Basic Research Programm of China(973 program,2009CB825300)the Shanghai Leading Academic Discipline Project(B108)for financial support
文摘Iron-catalyzed direct reduction of allylic halides with benzylic alcohol was achieved,providing a new,simple,and efficient method for conducting highly regioselective hydrodehalogenation.This method not only features a readily available reductant,an inexpensive catalyst,simple manipulation,and good tolerance of functional groups including nitriles,nitro,esters,and methoxyl groups,it also has mild reaction conditions and shows complete regioselectivity in that only halides sited at the allylic position are reduced.Alternatively,this method can be applied in the selective transformation of benzylic alcohols to aromatic aldehydes without overoxidation to carboxylic acids.
