The nickel(0)complex[Ni(^(iPr)PN)(COD)](^(iPr)PN=2-[(N-diisopropylphosphino)methylamino]pyridine,COD=1,5-cyclooctadiene)was an efficient precatalyst for the hydrodefluorination of pyridines employing pinacolborane(HBP...The nickel(0)complex[Ni(^(iPr)PN)(COD)](^(iPr)PN=2-[(N-diisopropylphosphino)methylamino]pyridine,COD=1,5-cyclooctadiene)was an efficient precatalyst for the hydrodefluorination of pyridines employing pinacolborane(HBPin).2-fluoro and 2,6-difluoropyridines were hydrodefluorinated at the 2-and 6-positions at room temperature in 3 h 30 min.The impact of the number of fluorine atoms and their position at the pyridyl ring in the efficiency of the catalyst was explored.Mechanistic experiments for the hydrodefluorination of 2,6-difluoropyridine allowed to identify COD decoordination followed by C–F oxidative addition as the catalyst entry pathway to the cycle and the[Ni(^(iPr)PN)(COD)]complex as the catalyst resting-state.The Ni(Ⅱ)fluoride complexes,[NiF(^(iPr)PN)(6-Fpy)](6-Fpy=6-fluoropyrid-2-yl)and[NiF(^(iPr)PN)(py)](py=2-pyridyl)were independently synthesized and identified as intermediates in the two subsequent hydrodefluorination cycles operative through single-turnover experiments.Both Ni(Ⅱ)fluoride complexes were found to be bench-stable precatalysts for the process with a comparable efficiency to[Ni(^(iPr)PN)(COD)]in the presence of a substoichiometric amount of COD to prevent catalyst deactivation.展开更多
Photocatalytic hydrodefluorination of perfluoroarenes by rhodium porphyrin complexes with high tolerance to various functional groups has been developed.Mechanistic studies reveal that the rhodium aryl complex,(por)Rh...Photocatalytic hydrodefluorination of perfluoroarenes by rhodium porphyrin complexes with high tolerance to various functional groups has been developed.Mechanistic studies reveal that the rhodium aryl complex,(por)Rh-C_(6)F_(4)R,is the key intermediate.展开更多
We reported herein a novel gold(I)bifluoride complex,LAuHF_(2),supported by a sterically bulky ligand(L,^(t)BuXantphos),that displays exceptional reactivity toward hydrodefluorination(HDF)and hydrosilylation of CO_(2)...We reported herein a novel gold(I)bifluoride complex,LAuHF_(2),supported by a sterically bulky ligand(L,^(t)BuXantphos),that displays exceptional reactivity toward hydrodefluorination(HDF)and hydrosilylation of CO_(2)in the presence of hydrosilanes.Compared to the LAuCl counterpart,the LAuHF_(2)complex exhibited an over 27-fold increase in turnover frequency in HDF and a 16-times higher turnover number in the hydrosilylation of CO_(2).展开更多
Fluorinated organic compounds are of great importance to modern industries,while their release to the environment is inevitable,causing extreme environmental pollution and the subsequent hazardous effect on ecosystems...Fluorinated organic compounds are of great importance to modern industries,while their release to the environment is inevitable,causing extreme environmental pollution and the subsequent hazardous effect on ecosystems.This is because the degradation of fluorinated compounds under mild conditions remains a challenging task due to the strong C-F bond strength.In this study,we report preparation of PdRu@MIL-101 through immobilizing ultrafine PdRu alloy nanoparticles with a mean diameter of∼2 nminto the metal-organic framework(MOF),MIL-101(Cr),which was highly active and stable in the hydrodefluorination of 4-fluorophenol(4-FP)under mild aqueous conditions.The optimized catalyst Pd0.5Ru0.5@MIL-101 achieved impressive hydrogenation performance with a 98.5% conversion of 4-FP and a 97.7% selectivity of cyclohexanol,much better than the single metal-doped Pd@MIL-101 and Ru@MIL-101 catalysts.The excellent catalytic behavior contributed to the synergistic effect of combining the PdRu alloying effect and the MOF nanospace confinement effect,providing a promising strategy to develop highly efficient hydrodefluorination catalysts to assist environmental restoration and green ecology.展开更多
An effective and facile method for preparation of partially fluorinated aromatics via Nickel catalyzed, chelation-assisted ortho selective hydrodefluorination of polyfluoroames with triethylsilane has been developed, ...An effective and facile method for preparation of partially fluorinated aromatics via Nickel catalyzed, chelation-assisted ortho selective hydrodefluorination of polyfluoroames with triethylsilane has been developed, in which N-containing heterocycles were used as directing groups. The advantage of this protocol is its simple catalytic system with use of inexpensive and readily available NiCl2·6H2O as a catalyst.展开更多
Planar organofluorine compounds are highly sought-after structural motifs.Herein,we present an enantioselective strategy for the synthesis of planar chiral fluoroalkenes via kinetic resolution of gem-difluorovinylferr...Planar organofluorine compounds are highly sought-after structural motifs.Herein,we present an enantioselective strategy for the synthesis of planar chiral fluoroalkenes via kinetic resolution of gem-difluorovinylferrocenes by copper-catalyzed hydrodefluorination in the presence of a base and diboron.This method was successfully applied to provide a diverse range of planar chiral gem-difluoroalkenes and Z-monofluoroalkenes with excellent regio-,stereo-and enantioselectivity.The resulting enantioenriched planar chiral fluoroalkenes could undergo various enantioretaining transformations,broadening their synthetic utility.Furthermore,density functional theory(DFT)calculations provide mechanistic insights into the origin of enantioselectivity,enhancing the understanding of this transformation.展开更多
基金supported by funds from the NSF LEAPS-MPS-CHE program(grant#2316526 to R.A.)the NSF MRI program(CHE-2216471)University of California,Merced,start-up funds for Rebeca Arevalo.
文摘The nickel(0)complex[Ni(^(iPr)PN)(COD)](^(iPr)PN=2-[(N-diisopropylphosphino)methylamino]pyridine,COD=1,5-cyclooctadiene)was an efficient precatalyst for the hydrodefluorination of pyridines employing pinacolborane(HBPin).2-fluoro and 2,6-difluoropyridines were hydrodefluorinated at the 2-and 6-positions at room temperature in 3 h 30 min.The impact of the number of fluorine atoms and their position at the pyridyl ring in the efficiency of the catalyst was explored.Mechanistic experiments for the hydrodefluorination of 2,6-difluoropyridine allowed to identify COD decoordination followed by C–F oxidative addition as the catalyst entry pathway to the cycle and the[Ni(^(iPr)PN)(COD)]complex as the catalyst resting-state.The Ni(Ⅱ)fluoride complexes,[NiF(^(iPr)PN)(6-Fpy)](6-Fpy=6-fluoropyrid-2-yl)and[NiF(^(iPr)PN)(py)](py=2-pyridyl)were independently synthesized and identified as intermediates in the two subsequent hydrodefluorination cycles operative through single-turnover experiments.Both Ni(Ⅱ)fluoride complexes were found to be bench-stable precatalysts for the process with a comparable efficiency to[Ni(^(iPr)PN)(COD)]in the presence of a substoichiometric amount of COD to prevent catalyst deactivation.
基金supported by the National Science Foundation of China(21322108 and 21321001).
文摘Photocatalytic hydrodefluorination of perfluoroarenes by rhodium porphyrin complexes with high tolerance to various functional groups has been developed.Mechanistic studies reveal that the rhodium aryl complex,(por)Rh-C_(6)F_(4)R,is the key intermediate.
基金the National Natural Science Foundation of China(NSFC)(21571007,21621061,21778002,and 21861162008)the Chemistry and Chemical Engineering Guangdong Laboratory(1932002)for financial supportsupported by the High-performance Computing Platform of Peking University。
文摘We reported herein a novel gold(I)bifluoride complex,LAuHF_(2),supported by a sterically bulky ligand(L,^(t)BuXantphos),that displays exceptional reactivity toward hydrodefluorination(HDF)and hydrosilylation of CO_(2)in the presence of hydrosilanes.Compared to the LAuCl counterpart,the LAuHF_(2)complex exhibited an over 27-fold increase in turnover frequency in HDF and a 16-times higher turnover number in the hydrosilylation of CO_(2).
基金supported by the National Key R&D Program of China(no.2018YFA0108300)the Overseas High-level Talents Plan of China and Guangdong Province,the Fundamental Research Funds for the Central Universities+2 种基金the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(no.2017Z T07C069)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(no.2017BT01C161)the NSFC Projects(nos.22075321,21821003,21890380,and 21905315).
文摘Fluorinated organic compounds are of great importance to modern industries,while their release to the environment is inevitable,causing extreme environmental pollution and the subsequent hazardous effect on ecosystems.This is because the degradation of fluorinated compounds under mild conditions remains a challenging task due to the strong C-F bond strength.In this study,we report preparation of PdRu@MIL-101 through immobilizing ultrafine PdRu alloy nanoparticles with a mean diameter of∼2 nminto the metal-organic framework(MOF),MIL-101(Cr),which was highly active and stable in the hydrodefluorination of 4-fluorophenol(4-FP)under mild aqueous conditions.The optimized catalyst Pd0.5Ru0.5@MIL-101 achieved impressive hydrogenation performance with a 98.5% conversion of 4-FP and a 97.7% selectivity of cyclohexanol,much better than the single metal-doped Pd@MIL-101 and Ru@MIL-101 catalysts.The excellent catalytic behavior contributed to the synergistic effect of combining the PdRu alloying effect and the MOF nanospace confinement effect,providing a promising strategy to develop highly efficient hydrodefluorination catalysts to assist environmental restoration and green ecology.
文摘An effective and facile method for preparation of partially fluorinated aromatics via Nickel catalyzed, chelation-assisted ortho selective hydrodefluorination of polyfluoroames with triethylsilane has been developed, in which N-containing heterocycles were used as directing groups. The advantage of this protocol is its simple catalytic system with use of inexpensive and readily available NiCl2·6H2O as a catalyst.
基金supported by the NSFC(No.22471063)the Natural Science Foundation of Henan Province(242300421351,252300421719)+1 种基金Education Department of Henan Province Natural Science Research Program(23A150037)Henan Postdoctoral Science Foundation(202103087)。
文摘Planar organofluorine compounds are highly sought-after structural motifs.Herein,we present an enantioselective strategy for the synthesis of planar chiral fluoroalkenes via kinetic resolution of gem-difluorovinylferrocenes by copper-catalyzed hydrodefluorination in the presence of a base and diboron.This method was successfully applied to provide a diverse range of planar chiral gem-difluoroalkenes and Z-monofluoroalkenes with excellent regio-,stereo-and enantioselectivity.The resulting enantioenriched planar chiral fluoroalkenes could undergo various enantioretaining transformations,broadening their synthetic utility.Furthermore,density functional theory(DFT)calculations provide mechanistic insights into the origin of enantioselectivity,enhancing the understanding of this transformation.
