The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydr...The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydrogen atom transfer strategy involving radicals has garnered considerable attention from chemists due to its high chemoselectivity and regioselectivity.However,owing to the marginal differences in bond dissociation energies(BDEs)among C(sp^(3))—H bonds,hydrogen atom transfer reactions mediated by alkyl radicals remain less-developed.A copper-catalyzed sulfone-induced regioselective C(sp^(3))—H bond heteroarylation reaction was reported.This strategy utilizes theα-alkyl radical of sulfone as an intramolecular hydrogen abstraction reagent,enabling the regioselective formation of carbon-nitrogen bonds under copper catalysis.展开更多
A rhodium-catalyzed desymmetrization reaction for enantioselective methyl C-H arylation is achieved by utilizing an in situ arylating reagent via nucleophilic cyclization of o-aminoaryl alkyne.The reaction results in ...A rhodium-catalyzed desymmetrization reaction for enantioselective methyl C-H arylation is achieved by utilizing an in situ arylating reagent via nucleophilic cyclization of o-aminoaryl alkyne.The reaction results in chiral indoles containing all-carbon quaternary stereocenters under atmospheric conditions,with a wide range of substrates exhibiting good enantioselectivity(44 examples).Mechnism and DFT studies show that the stereocontrol is reasonably achieved through the collaborative control of a large silicon substituted chiral ligand and C-H···π,LP···πinteractions between aryl rings of the carboxylate group and the substrate.Control experiments demonstrate that Rh-aryl bond formation via in situ nucleophilic cyclization is more critical for reaction efficiency than via C-H activation of the nucleophilic cyclization byproduct.展开更多
Asymmetric cascade Heck/C–H functionalization has emerged as an appealing strategy for activating inert C–H bonds and conveniently synthesizing heterocycles with quaternary centers,owing to the domino sequence of ca...Asymmetric cascade Heck/C–H functionalization has emerged as an appealing strategy for activating inert C–H bonds and conveniently synthesizing heterocycles with quaternary centers,owing to the domino sequence of carbopalladation followed by C–H functionalization enabling efficient construction of multiple bonds in one pot.Herein,a palladium-catalyzed enantioselective cascade Heck/intermolecular direct heteroarylation reaction of unactivated alkenes with heteroarenes is developed,providing a facile access to diverse bis-heterocycles of great practicality bearing an all-carbon quaternary stereocenter with excellent levels of yields and enantioselectivities under mild conditions.Moreover,the synthetic utility of this strategy is further demonstrated by the versatile transformations of product.展开更多
A conceptually novel,trifunctional sulfoximine-mediatedγ-functionalization of unactivated C(sp^(3))–H bonds has been achieved.The reaction is initiated by the photo-induced homolytic cleavage of an N–S bond in the ...A conceptually novel,trifunctional sulfoximine-mediatedγ-functionalization of unactivated C(sp^(3))–H bonds has been achieved.The reaction is initiated by the photo-induced homolytic cleavage of an N–S bond in the absence of photosensitizer,and proceeds sequentially through a cascade of 1,5-hydrogen atom transfer,1,4-functional group migration,desulfoximination and a Minisci reaction.A major feature of this approach is the use of sulfoximine as a traceless directing group.Other positive properties include mild conditions,simple operation,exclusive site-selectivity,high product diversity and the avoidance of additional photosensitizers.The protocol provides a new reaction mode for HAT-induced C(sp^(3))–H functionalization,and allows a much broader chemical space for sulfoximine studies.展开更多
A series of new bisphosphine-monoxide(BPMO)ligands based on benzothiophene backbone and the corresponding palladium complexes{k2-P(O)(Ph)2-3-PR1R2-C8H4S}PdMeCl{2a:R1=R2=Ph;2b:R1=R2=2-0Me-Ph;2c:R1=R2=2-CF3-Ph;2d:Rl=Ph,...A series of new bisphosphine-monoxide(BPMO)ligands based on benzothiophene backbone and the corresponding palladium complexes{k2-P(O)(Ph)2-3-PR1R2-C8H4S}PdMeCl{2a:R1=R2=Ph;2b:R1=R2=2-0Me-Ph;2c:R1=R2=2-CF3-Ph;2d:Rl=Ph,R2=2-(2',6'-(OMe)2C6Hz)-C6H4}were synthesized and fully characterized by1H-,13C-,31P-,and 2D-NMR spectroscopy and single-crystal X-ray dfraction.In the presence of Na+B[3,5-(CF3)2C6H3]4(NaBArF),these complexes showed very high activities(up to 2.0 x 10’g-mol-1.h-)for ethylene polymerization.More significantly,these catalysts enabled the copolymerization of ethylene with a broad scope of commercially available polar comonomers such as acrylates,acrylic acid,acrylonitrile,vinyltrialkoxysilane,allyl acetate,and long-chain 6-chloro-1-hexene to give functionalized polyethylene with reasonable catalytic activities(up to 105 g-mol-l.h-)and incorporations(up to 5.3 mol96).This contribution suggests that,besides the modulation of conventionally steric and electronic factors,the connectivity(at dfferent linking positions)of BPMO(P,O)donors to the heteroaryl backbone also greatly infuences the catalyst properties in terms of catalytic activity,polymer branching content,comonomer scope,and comonomer incorporation.展开更多
Highly active, air-stable and water-soluble palladium-phosphinous acid complexes have been applied to Suzuki cross-coupling reaction of heteroaryl bromides under mild conditions in water/alcoholic solvents. Suzuki cro...Highly active, air-stable and water-soluble palladium-phosphinous acid complexes have been applied to Suzuki cross-coupling reaction of heteroaryl bromides under mild conditions in water/alcoholic solvents. Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid occurred efficiently using palladium phosphinous acid complexes （POPd） and phase transfer catalyst （tetrabutylammonium bromide and polyethylene glycol） in water/ethanol mixture, water/propanol mixture and neat water respectively, the corresponding yields of cross-coupling heteroaryl-aryls were satisfied. The tert-butyl substituted ligand di-tert-butylphosphino in combination with POPd was found to be more active than the same family derived catalysts dipalladium complexes POPdl and POPd2, and other two kinds of Pd-catalysts Pd（PPh3）4 and Pd2（dba）3. The mechanism of Suzuki cross-coupling reaction between heteroaryl bromides and phenylboronic acid in water was proposed with respect to the key role of phase transfer catalyst on the transmetallation step. Compared with other solid phase transfer catalysts, TBAB was tested as the ideal one. The alkalinity of base and the molar proportion between POPd and TBAB were investigated in water and alcoholic solvents. Notably, in the presence of TBAB adding alcoholic solvents into water enhanced the yields of target products. However in terms of the liquid phase transfer catalyst of PEGs, mixing water into PEGs could slightly decrease the yields with respect to the water free PEGs bulk phase, which was probably due to the homogenous liquid conditions in pure PEGs and weak interactions between PEGs and heteroaryl bromide molecules in water depending on their molecular chain lengths.展开更多
Boric acid （BO3H3） is an inexpensive, efficient and mild catalyst for the synthesis of 1,1-diacetate （acylal） from the various aromatic and heteroaryl aldehydes with acetic anhydride at room temperature under solv...Boric acid （BO3H3） is an inexpensive, efficient and mild catalyst for the synthesis of 1,1-diacetate （acylal） from the various aromatic and heteroaryl aldehydes with acetic anhydride at room temperature under solvent-free condition. The present method does not involve any hazardous organic solvents or catalysts. This method gives notable advantages such as excellent chemoselectivity, mild reaction condition, short reaction times and excellent yield.展开更多
Ultrasonic and microwave-assisted practical methods have been developed for the O-alkylation of aryl (β-naphthols) and Heteroaryl (hydroxy pyridines) in aqueous surfactant media in good to excellent yields. The devel...Ultrasonic and microwave-assisted practical methods have been developed for the O-alkylation of aryl (β-naphthols) and Heteroaryl (hydroxy pyridines) in aqueous surfactant media in good to excellent yields. The developed methods are simple, efficient, economical and environmentally safe. Our novel methods describe a set of green methods to Wil-liamson synthesis.展开更多
Comprehensive Summary Herein,we have developed a strategy of Rh(III)-catalyzed C—H activation of N-nitrosoanilines and iodonium ylides to construct novel tetralydrocarbzol-4-one scaffolds,which provided valuable temp...Comprehensive Summary Herein,we have developed a strategy of Rh(III)-catalyzed C—H activation of N-nitrosoanilines and iodonium ylides to construct novel tetralydrocarbzol-4-one scaffolds,which provided valuable templates for sequential C—H functionalization such as alkylation,alkenylation,amidation and(hetero)arylation at C^(5)-position of tetralydrocarbzol-4-one with different coupling partners.Gram-scale synthesis and further transformations of tetralydrocarbzol-4-one derivatives to Ondansetron and its analogues demonstrated the utility of this protocol,which enabled the concise and diverse construction of biologically active molecules.展开更多
Transition-metal-catalyzed direct C–H/C–H cross-coupling reactions as efficient and atom-economical approaches have been widely used to build up complex heterocyclic compounds.However,the strategy for preparation of...Transition-metal-catalyzed direct C–H/C–H cross-coupling reactions as efficient and atom-economical approaches have been widely used to build up complex heterocyclic compounds.However,the strategy for preparation of biphenyl-2-carbonitriles has not been well established.Herein,we described the first cyanogen directed Rh(III)-catalyzed CDC reaction of aromatic nitriles with heteroarenes.Various biphenyl-2-carbonitrilederivatives were obtained with broad functional group compatibility.展开更多
Photocatalyzed alkylsulfonylation of unactivated alkenes using DABCO.(SO_(2))_(2) and thianthrenium salts via a distal heteroaryl migration process has been developed,which provides a new means of synthesizing a varie...Photocatalyzed alkylsulfonylation of unactivated alkenes using DABCO.(SO_(2))_(2) and thianthrenium salts via a distal heteroaryl migration process has been developed,which provides a new means of synthesizing a variety of valuable alkylsulfonyl-substituted compounds.These alkylsulfonyl radicals couple with unactivated alkenes to undergo efficient intermolecular reactions,followed by distal heteroaryl migration.This mild catalytic method is tolerant of functional groups and affords medicinally relevant alkylsulfonylated heterocycles.展开更多
By optimizing the reaction conditions via a careful screening of the bases and solvents, we developed an efficient transition metal-free method for C--O cross-coupling of activated and unactivated heteroaryl chlorides...By optimizing the reaction conditions via a careful screening of the bases and solvents, we developed an efficient transition metal-free method for C--O cross-coupling of activated and unactivated heteroaryl chlorides with primary and secondary alcohols and phenols, providing a simple, efficient, and practical method for synthesis of the useful unsymmetrical heteroaryl alkyl and heteroaryl aryl ethers.展开更多
The preparation of heteroaryl trifluoromethyl selenoethers by the trifluoromethylselenolation of heteroaryl bro- mides with [（bpy）CuSeCF3]2 was investigated. Using this approach, a large number of trifluoromethylsel...The preparation of heteroaryl trifluoromethyl selenoethers by the trifluoromethylselenolation of heteroaryl bro- mides with [（bpy）CuSeCF3]2 was investigated. Using this approach, a large number of trifluoromethylselenolated heterocyclic compounds were synthesized in good to excellent yields. It was demonstrated that this procedure toler- ates a wide variety of functional groups.展开更多
A direct and efficient approach to 1-aminoindolizines through three-component one-pot reaction of heteroaryl aldehydes, secondary amines and terminal alkynes catalyzed by CuI under solvent-free conditions has been dev...A direct and efficient approach to 1-aminoindolizines through three-component one-pot reaction of heteroaryl aldehydes, secondary amines and terminal alkynes catalyzed by CuI under solvent-free conditions has been developed. This methodology provides a rapid access to substituted aminoindolizines with good yields （up to 97%）.展开更多
The asymmetric reduction of carbonyl compounds by means of the Ru-chiral diphosphine-chiral diamine catalysts is widely useful in organic synthesis where high levels of enantioselectivities have been attributed to mul...The asymmetric reduction of carbonyl compounds by means of the Ru-chiral diphosphine-chiral diamine catalysts is widely useful in organic synthesis where high levels of enantioselectivities have been attributed to multiple ligand chiral elements as well as essential stereochemical matching synergies within them.Described here is the design and discovery of new pincer-type Ru-catalysts that feature only single stereogenic element within ligands,yet the such significantly simplified structure is demonstrated to be well competent for effecting asymmetric reductions as well as kinetic resolutions over a broad range of highly functionalized ketones/alcohols,including heteroaryl substituted substrates that were challenging by known catalyst systems.Alcohols were furnished not only in excellent enantioselectivities,but with turnover numbers(up to 100,000 TONs)that reach the highest levels known to date in asymmetric transfer hydrogenation of ketones.This work should help shed light on the intricate origin of enantioselection in these important processes,and further stimulate rational understanding as well as optimization of chiral catalysts towards efficiency and simplicity.展开更多
The site-selective C-H fluorination of heteroarenes is a straightforward approach to accessing valuable heteroaryl fluorides but remains a formidable challenge.Herein,we report a general strategy for visible-light-ind...The site-selective C-H fluorination of heteroarenes is a straightforward approach to accessing valuable heteroaryl fluorides but remains a formidable challenge.Herein,we report a general strategy for visible-light-induced C-H fluorination of heteroarenes via the merger of N-F fluorinating reagents and silane.Electron paramagnetic resonance experiments provide evidence for the homolytic cleavage of the N-F bond under blue light-emitting diode irradiation,which is the key step in the process.This transformation is metal-free,photocatalysts-free,and site-selective under mild reaction conditions(ambient temperature,visible-light irradiation,tolerant to H2O).The robustness of this protocol has also been highlighted by late-stage modification of complex and medicinally relevant molecules.展开更多
文摘The regioselective carbon-hydrogen bond functionalization reaction in atom-and step-economy holds significant potential for the late-stage elaboration of complex molecules and natural products.In recent years,the hydrogen atom transfer strategy involving radicals has garnered considerable attention from chemists due to its high chemoselectivity and regioselectivity.However,owing to the marginal differences in bond dissociation energies(BDEs)among C(sp^(3))—H bonds,hydrogen atom transfer reactions mediated by alkyl radicals remain less-developed.A copper-catalyzed sulfone-induced regioselective C(sp^(3))—H bond heteroarylation reaction was reported.This strategy utilizes theα-alkyl radical of sulfone as an intramolecular hydrogen abstraction reagent,enabling the regioselective formation of carbon-nitrogen bonds under copper catalysis.
基金financial support for this work from the National Key R&D Program of China(No.2021YFC0864700)the National Natural Science Foundation of China(Nos.21801066,U1804283 and 82130103)+2 种基金the Central Plains Scholars and Scientists Studio Fund(No.2018002)the project funded by the Natural Science Foundation of Henan(Nos.222300420056,222300420204)the China Postdoctoral Science Foundation(Nos.2020M682307,2021T140183)。
文摘A rhodium-catalyzed desymmetrization reaction for enantioselective methyl C-H arylation is achieved by utilizing an in situ arylating reagent via nucleophilic cyclization of o-aminoaryl alkyne.The reaction results in chiral indoles containing all-carbon quaternary stereocenters under atmospheric conditions,with a wide range of substrates exhibiting good enantioselectivity(44 examples).Mechnism and DFT studies show that the stereocontrol is reasonably achieved through the collaborative control of a large silicon substituted chiral ligand and C-H···π,LP···πinteractions between aryl rings of the carboxylate group and the substrate.Control experiments demonstrate that Rh-aryl bond formation via in situ nucleophilic cyclization is more critical for reaction efficiency than via C-H activation of the nucleophilic cyclization byproduct.
基金funding support of the National Key R&D Program of China(No.2021YFF0701600)NSFC(No.22031004)+1 种基金the Shanghai Municipal Education Commission(No.20212308)STCSM(No.23ZR1445600).
文摘Asymmetric cascade Heck/C–H functionalization has emerged as an appealing strategy for activating inert C–H bonds and conveniently synthesizing heterocycles with quaternary centers,owing to the domino sequence of carbopalladation followed by C–H functionalization enabling efficient construction of multiple bonds in one pot.Herein,a palladium-catalyzed enantioselective cascade Heck/intermolecular direct heteroarylation reaction of unactivated alkenes with heteroarenes is developed,providing a facile access to diverse bis-heterocycles of great practicality bearing an all-carbon quaternary stereocenter with excellent levels of yields and enantioselectivities under mild conditions.Moreover,the synthetic utility of this strategy is further demonstrated by the versatile transformations of product.
基金supported by the National Natural Science Foundation of China(21971173,22001185,22171201)the Natural Science Foundation of Jiangsu Province(BK20200852)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘A conceptually novel,trifunctional sulfoximine-mediatedγ-functionalization of unactivated C(sp^(3))–H bonds has been achieved.The reaction is initiated by the photo-induced homolytic cleavage of an N–S bond in the absence of photosensitizer,and proceeds sequentially through a cascade of 1,5-hydrogen atom transfer,1,4-functional group migration,desulfoximination and a Minisci reaction.A major feature of this approach is the use of sulfoximine as a traceless directing group.Other positive properties include mild conditions,simple operation,exclusive site-selectivity,high product diversity and the avoidance of additional photosensitizers.The protocol provides a new reaction mode for HAT-induced C(sp^(3))–H functionalization,and allows a much broader chemical space for sulfoximine studies.
基金the National Natural Science Foundation of China(No.21871250)the Jilin Provincial Science and Technology Department Program(No.20190201009JC)Shaanxi Provincial Natural Science Basic Research Program-Shaanxi Coal and Chemical Industry Group Co,Ltd.Joint Fund(No.2019JLZ-02).
文摘A series of new bisphosphine-monoxide(BPMO)ligands based on benzothiophene backbone and the corresponding palladium complexes{k2-P(O)(Ph)2-3-PR1R2-C8H4S}PdMeCl{2a:R1=R2=Ph;2b:R1=R2=2-0Me-Ph;2c:R1=R2=2-CF3-Ph;2d:Rl=Ph,R2=2-(2',6'-(OMe)2C6Hz)-C6H4}were synthesized and fully characterized by1H-,13C-,31P-,and 2D-NMR spectroscopy and single-crystal X-ray dfraction.In the presence of Na+B[3,5-(CF3)2C6H3]4(NaBArF),these complexes showed very high activities(up to 2.0 x 10’g-mol-1.h-)for ethylene polymerization.More significantly,these catalysts enabled the copolymerization of ethylene with a broad scope of commercially available polar comonomers such as acrylates,acrylic acid,acrylonitrile,vinyltrialkoxysilane,allyl acetate,and long-chain 6-chloro-1-hexene to give functionalized polyethylene with reasonable catalytic activities(up to 105 g-mol-l.h-)and incorporations(up to 5.3 mol96).This contribution suggests that,besides the modulation of conventionally steric and electronic factors,the connectivity(at dfferent linking positions)of BPMO(P,O)donors to the heteroaryl backbone also greatly infuences the catalyst properties in terms of catalytic activity,polymer branching content,comonomer scope,and comonomer incorporation.
基金supported by the Natural Science Foundation of Liaoning Education Department (No. 2008T094)
文摘Highly active, air-stable and water-soluble palladium-phosphinous acid complexes have been applied to Suzuki cross-coupling reaction of heteroaryl bromides under mild conditions in water/alcoholic solvents. Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid occurred efficiently using palladium phosphinous acid complexes （POPd） and phase transfer catalyst （tetrabutylammonium bromide and polyethylene glycol） in water/ethanol mixture, water/propanol mixture and neat water respectively, the corresponding yields of cross-coupling heteroaryl-aryls were satisfied. The tert-butyl substituted ligand di-tert-butylphosphino in combination with POPd was found to be more active than the same family derived catalysts dipalladium complexes POPdl and POPd2, and other two kinds of Pd-catalysts Pd（PPh3）4 and Pd2（dba）3. The mechanism of Suzuki cross-coupling reaction between heteroaryl bromides and phenylboronic acid in water was proposed with respect to the key role of phase transfer catalyst on the transmetallation step. Compared with other solid phase transfer catalysts, TBAB was tested as the ideal one. The alkalinity of base and the molar proportion between POPd and TBAB were investigated in water and alcoholic solvents. Notably, in the presence of TBAB adding alcoholic solvents into water enhanced the yields of target products. However in terms of the liquid phase transfer catalyst of PEGs, mixing water into PEGs could slightly decrease the yields with respect to the water free PEGs bulk phase, which was probably due to the homogenous liquid conditions in pure PEGs and weak interactions between PEGs and heteroaryl bromide molecules in water depending on their molecular chain lengths.
文摘Boric acid （BO3H3） is an inexpensive, efficient and mild catalyst for the synthesis of 1,1-diacetate （acylal） from the various aromatic and heteroaryl aldehydes with acetic anhydride at room temperature under solvent-free condition. The present method does not involve any hazardous organic solvents or catalysts. This method gives notable advantages such as excellent chemoselectivity, mild reaction condition, short reaction times and excellent yield.
文摘Ultrasonic and microwave-assisted practical methods have been developed for the O-alkylation of aryl (β-naphthols) and Heteroaryl (hydroxy pyridines) in aqueous surfactant media in good to excellent yields. The developed methods are simple, efficient, economical and environmentally safe. Our novel methods describe a set of green methods to Wil-liamson synthesis.
基金the National Natural Science Foundation of China(Nos.82130105,82103969 and 82273766)SA-SIBS Scholarship Program,the Youth Innovation Promotion Association CAS(2020282)grant from Lingang Laboratory(LG202103-02-06).
文摘Comprehensive Summary Herein,we have developed a strategy of Rh(III)-catalyzed C—H activation of N-nitrosoanilines and iodonium ylides to construct novel tetralydrocarbzol-4-one scaffolds,which provided valuable templates for sequential C—H functionalization such as alkylation,alkenylation,amidation and(hetero)arylation at C^(5)-position of tetralydrocarbzol-4-one with different coupling partners.Gram-scale synthesis and further transformations of tetralydrocarbzol-4-one derivatives to Ondansetron and its analogues demonstrated the utility of this protocol,which enabled the concise and diverse construction of biologically active molecules.
基金We are grateful for the financial support from the National Natural Science Foundation of China(No.21572138)Key Laboratory of DrugTargeting and Drug Delivery System of the Education Ministry,Sichuan Research Center for Drug Precision Industrial Technology,111 Project B18035 and“the Fundamental Research Funds for the Central Universities”.
文摘Transition-metal-catalyzed direct C–H/C–H cross-coupling reactions as efficient and atom-economical approaches have been widely used to build up complex heterocyclic compounds.However,the strategy for preparation of biphenyl-2-carbonitriles has not been well established.Herein,we described the first cyanogen directed Rh(III)-catalyzed CDC reaction of aromatic nitriles with heteroarenes.Various biphenyl-2-carbonitrilederivatives were obtained with broad functional group compatibility.
基金the National Natural Science Foundation of China(Nos.21702103 and 21522604)the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture(No.XTD2203)+1 种基金the Natural Science Research Projects of Jiangsu Higher Education(No.19KJB150027)Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB389).
文摘Photocatalyzed alkylsulfonylation of unactivated alkenes using DABCO.(SO_(2))_(2) and thianthrenium salts via a distal heteroaryl migration process has been developed,which provides a new means of synthesizing a variety of valuable alkylsulfonyl-substituted compounds.These alkylsulfonyl radicals couple with unactivated alkenes to undergo efficient intermolecular reactions,followed by distal heteroaryl migration.This mild catalytic method is tolerant of functional groups and affords medicinally relevant alkylsulfonylated heterocycles.
文摘By optimizing the reaction conditions via a careful screening of the bases and solvents, we developed an efficient transition metal-free method for C--O cross-coupling of activated and unactivated heteroaryl chlorides with primary and secondary alcohols and phenols, providing a simple, efficient, and practical method for synthesis of the useful unsymmetrical heteroaryl alkyl and heteroaryl aryl ethers.
文摘The preparation of heteroaryl trifluoromethyl selenoethers by the trifluoromethylselenolation of heteroaryl bro- mides with [（bpy）CuSeCF3]2 was investigated. Using this approach, a large number of trifluoromethylselenolated heterocyclic compounds were synthesized in good to excellent yields. It was demonstrated that this procedure toler- ates a wide variety of functional groups.
文摘A direct and efficient approach to 1-aminoindolizines through three-component one-pot reaction of heteroaryl aldehydes, secondary amines and terminal alkynes catalyzed by CuI under solvent-free conditions has been developed. This methodology provides a rapid access to substituted aminoindolizines with good yields （up to 97%）.
基金supported by Shenzhen Nobel Prize Scientists Laboratory Project(C17783101)Shenzhen YOUWEI Tech Group,Guangdong Provincial Key Laboratory of Catalysis(2020B121201002)+2 种基金the Natural Science Foundation of Guangdong Province(2021A1515010329)the National Natural Science Foundation of China(22171128)Shenzhen Science and Technology Program(KQTD20180411143514543,JCYJ20190809143611743)。
文摘The asymmetric reduction of carbonyl compounds by means of the Ru-chiral diphosphine-chiral diamine catalysts is widely useful in organic synthesis where high levels of enantioselectivities have been attributed to multiple ligand chiral elements as well as essential stereochemical matching synergies within them.Described here is the design and discovery of new pincer-type Ru-catalysts that feature only single stereogenic element within ligands,yet the such significantly simplified structure is demonstrated to be well competent for effecting asymmetric reductions as well as kinetic resolutions over a broad range of highly functionalized ketones/alcohols,including heteroaryl substituted substrates that were challenging by known catalyst systems.Alcohols were furnished not only in excellent enantioselectivities,but with turnover numbers(up to 100,000 TONs)that reach the highest levels known to date in asymmetric transfer hydrogenation of ketones.This work should help shed light on the intricate origin of enantioselection in these important processes,and further stimulate rational understanding as well as optimization of chiral catalysts towards efficiency and simplicity.
基金financial support from the National Natural Science Foundation of China (grant no.22201121)Jiangxi Provincial Natural Science Foundation (grant nos.20224BAB213006 and 20232BAB203002).
文摘The site-selective C-H fluorination of heteroarenes is a straightforward approach to accessing valuable heteroaryl fluorides but remains a formidable challenge.Herein,we report a general strategy for visible-light-induced C-H fluorination of heteroarenes via the merger of N-F fluorinating reagents and silane.Electron paramagnetic resonance experiments provide evidence for the homolytic cleavage of the N-F bond under blue light-emitting diode irradiation,which is the key step in the process.This transformation is metal-free,photocatalysts-free,and site-selective under mild reaction conditions(ambient temperature,visible-light irradiation,tolerant to H2O).The robustness of this protocol has also been highlighted by late-stage modification of complex and medicinally relevant molecules.
