Ferrocenyliminophosphine 1 and 1,1′-bisferrocenyliminophosphine 2 were easily prepared from the condensation of formylferrocene or 1,1′-diformylferrocene with 2-(diphenylphosphino) aniline. The following reduction...Ferrocenyliminophosphine 1 and 1,1′-bisferrocenyliminophosphine 2 were easily prepared from the condensation of formylferrocene or 1,1′-diformylferrocene with 2-(diphenylphosphino) aniline. The following reduction of imine group by LiAlH4 led to the formation of the corresponding ferrocenyl amidophosphines 3 and 4. The new ligands 2- 4 were well characterized by IR, ^1H NMR, ^31p NMR spectra, elemental analysis, and ESI-MS. The catalytic activity of all the ligands with palladium compounds in the Suzuki reaction was evaluated. Ligand 1, in combination with Pd (OAc)2, was found to be the most effective for the Suzuki reaction of aryl bromides with phenylboronic acid. Typically, the use of 0. 1% (molar fraction) of Pd(OAc)2/ligand 1 in the presence of two equivalents of K2CO3 as base in toluene at 110 ℃ provided good to excellent yields of the coupled products.展开更多
The new complexes, [PdCl{C5H4FeC5H4CHRN=CHC4H3O}(Ph3P)] (R= H, CH3) were synthesized via two novel Schiff bases (C5H5FeC5H4CHRN=CHC4H3O, R= H, CH3) with lithium tetrachloropalladate (Ⅱ), and characterized by ...The new complexes, [PdCl{C5H4FeC5H4CHRN=CHC4H3O}(Ph3P)] (R= H, CH3) were synthesized via two novel Schiff bases (C5H5FeC5H4CHRN=CHC4H3O, R= H, CH3) with lithium tetrachloropalladate (Ⅱ), and characterized by IR, elemental analysis, ^1H NMR. Complex 5a was further determined by X-ray single crystal diffraction. We found that it contained an intramolecular N→Pd coordination in the compound 5a, and the palladium atom was bound to the unsubstituted Cp ring. The Pd-N, Pd-C (I) and Pd-O bond lengths were 2.121 (3), 2.008 (4) and 2.990 )A, respectively.展开更多
A visible-light-promoted formal[2+2+1]cyclization of N-aryl glycines with quinoxalin-2(1H)-ones to synthesize tetrahydroimidazo[1,5-a]quinoxalin-4(5H)-ones have been developed.The protocol features operational simplic...A visible-light-promoted formal[2+2+1]cyclization of N-aryl glycines with quinoxalin-2(1H)-ones to synthesize tetrahydroimidazo[1,5-a]quinoxalin-4(5H)-ones have been developed.The protocol features operational simplicity,mild reaction conditions with blue LED light employing Ru(bpy)3Cl2.6H2O as a photoredox catalyst,a combination of O2 from air and Cu(OAc)2 as the oxidant and broad substrate applicability.展开更多
A series of europium(III) complexes with different chain length, tris [2-m-pyridylmethanamido-5-phenyl- (1,3,4)-oxadiazole] mono [2-(4-n-alkylphenyl)-iminazole (4,5-f)-1,10-phenanthroline] Eu(III) [Eu(PMA)3Nn (n = 6, ...A series of europium(III) complexes with different chain length, tris [2-m-pyridylmethanamido-5-phenyl- (1,3,4)-oxadiazole] mono [2-(4-n-alkylphenyl)-iminazole (4,5-f)-1,10-phenanthroline] Eu(III) [Eu(PMA)3Nn (n = 6, 10, 14,18)] were synthesized. All of these amphiphilic europium(III) complexes could form stable Langmuir film at air/water interface and could be transferred onto hydrophilic quartz and mica substrates by measurement of UV spectra in which the absorbance of the LB films at about 288 nm scales showed the linearity with the number of layers deposited. In order to investigate relation between fluorescence properties and the arrangement of molecular in LB films, surface topography of monolayer films were observed by atomic force microscopy (AFM). Results showed that the emission spectra have Eu(III) characteristic peaks and strong emission strength. It is interesting that the molecular with looser arrangement in LB films has better monochromacity, which illustrated that energy might transferred more easily from ligand to Eu(III) in loosen structure films.展开更多
Achieving highly regioselective synthesis in organic chemistry is challenging due to the uncontrollable orientation between reacting partners.External electric fields(EEFs)can influence the reactivity and selectivity ...Achieving highly regioselective synthesis in organic chemistry is challenging due to the uncontrollable orientation between reacting partners.External electric fields(EEFs)can influence the reactivity and selectivity of the substrate by causing directional adsorption.However,scalable and efficient techniques for using EEFs as“smart catalysts”have been lacking,hindering their application.In this study,we present a novel method for modifying the regioselectivity of quinoxaline-2(1H)-ones by functionalizing their C7-position using the electric double layer(EDL)theory.This approach led to moderate to good yields of the corresponding C7-thiocyanation products.DFT calculations and control experiments demonstrated that EEFs could reverse the regioselectivity of quinoxaline-2(1H)-ones,allowing the C7-thiocyanation to proceed via a radical reaction mechanism.Additionally,the resulting 7-thiocyano-1-methylquinoxaline-2(1H)-ones exhibited promising AIE properties.Our work showcases a promising strategy for achieving highly regioselective functionalization by aligning the electric field with the desired reaction/bond axis.展开更多
Anthrones are key structural motifs in many natural products, bioactive compounds and pharmaceutical chemicals. Earth-abundant-metal-catalyzed asymmetric functionalization of anthrones has not proved to be viable. Her...Anthrones are key structural motifs in many natural products, bioactive compounds and pharmaceutical chemicals. Earth-abundant-metal-catalyzed asymmetric functionalization of anthrones has not proved to be viable. Herein, we disclosed a highly enantioselective propargylic substitution of anthrones with propargylic esters using copper salts with chiral N, N, P-ligand. This strategy is amenable to a broad range of substrates, uses readily available starting materials, provides excellent yields with remarkable enantioselectivity under mild conditions, and enables attractive products diversification routes.展开更多
A Ru(Ⅲ)-catalyzed annulation reaction of 2-aminoaromatic aldehydes(ketones)and isoxazoles to afford diverse 3-cyanoquinolines has been developed.Notably,isoxazole acted as a cyclization reagent and nontoxic cyano sou...A Ru(Ⅲ)-catalyzed annulation reaction of 2-aminoaromatic aldehydes(ketones)and isoxazoles to afford diverse 3-cyanoquinolines has been developed.Notably,isoxazole acted as a cyclization reagent and nontoxic cyano source via N-O bond cleavage and fragmentation.Variously substituted(especially 6-or 7-substituted)quinolines could be easily afforded.This procedure features wide functional group compatibility,efficiency and avoiding toxic cyano source.Meanwhile,this protocol could be successfully applied to scale-up synthesis.Further chemical transformations of 3-cyanoquinoline could give some valuable skeletons,demonstrating its potential in synthetic application.展开更多
The visible light promoted C-H sulfonylmethylation of imidazopyridines with easily accessible bromomethyl sulfones under mild reaction conditions was described.This protocol provides an effective and practical access ...The visible light promoted C-H sulfonylmethylation of imidazopyridines with easily accessible bromomethyl sulfones under mild reaction conditions was described.This protocol provides an effective and practical access to sulfonylmethylated imidazopyridines with good functional group tolerance.The desired products were provided in moderate to excellent yields for 50 examples at room temperature.The method could also be an attractive strategy to install a methyl group on imidazopyridines.展开更多
Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides....Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.展开更多
A selective ring-opening [3+2] cyclization reaction of benzo[d]isoxazoles with 2-bromo-propanamides has been developed.The azaoxyallyl cation intermediates are employed as C^O 3-atom synthon to build oxa-heterocycles ...A selective ring-opening [3+2] cyclization reaction of benzo[d]isoxazoles with 2-bromo-propanamides has been developed.The azaoxyallyl cation intermediates are employed as C^O 3-atom synthon to build oxa-heterocycles via the selectivity of suitable cyclization partners.This transformation provides rapid access to highly functionalized 2-hydroxyaryl-oxazolines under mild conditions and excellent regioselectivity.展开更多
A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(Ⅲ)-catalyzed [4+2] annulation of N-arylbenzamidines with 1,4,2-dioxazol-5-ones.This reaction features excellent regioselectivit...A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(Ⅲ)-catalyzed [4+2] annulation of N-arylbenzamidines with 1,4,2-dioxazol-5-ones.This reaction features excellent regioselectivity,broad substrate scope and high step economy,which would provide the refe rence for the construction of the fused 4-aminoquinazolines with biologically and pharmacologically active compounds.展开更多
A green tandem reaction,including insertion/aerobic oxidation/bisindolylation,starting from indoles and diazo compounds has been developed.The combination of water and fluorinated alcohol plays dual roles as solvent a...A green tandem reaction,including insertion/aerobic oxidation/bisindolylation,starting from indoles and diazo compounds has been developed.The combination of water and fluorinated alcohol plays dual roles as solvent and promoter in this chemical transformation.Molecular oxygen in the air acts as an oxidant.3,3’-Bis(indolyl)methanes with quaternary carbon were produced under metal-free conditions.No any catalyst and additive were required.N2 and water were released as sole by-products.Absence of water and fluorinated alcohol resulted in Wolff rearrangement product.展开更多
Due to using (R)- or (S)-a-methylbenzylamine as a chiral auxiliary, and low-temperature regime for reduction of the intermediate ferrocenyl-mono- or 1,1'-bis-ketimines, the corresponding secondary mono- or 1,1'-...Due to using (R)- or (S)-a-methylbenzylamine as a chiral auxiliary, and low-temperature regime for reduction of the intermediate ferrocenyl-mono- or 1,1'-bis-ketimines, the corresponding secondary mono- or 1,1'-bis-amines were prepared with high diastereoselectivity. Removal of the a-methylbenzyl group afforded the optically active primary mono- and bis-ferrocenylethylamines in high yields. The absolute configuration of (R,R)-3a and (S,S)-3b was determined by X-ray single crystal diffraction.展开更多
An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. ...An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. This chlori- nation was not a ligand-directed ortho-C--H activation, but an electrophilic substitution process at the para-position of the nitrogen atom in the benzo ring of benzoxazole moiety, the regiochemistry of which had been confirmed by HMBC spectral analysis. The catalytic system could tolerate various halogen atoms, such as F, Cl and Br, affording the corresponding products in moderate to excellent yields.展开更多
A variety of 2-arylnaphtho[ 1,2-d]oxazole derivatives were efficiently synthesized in moderate to high yields by the reaction of aromatic aldehydes with 1-amino-2-naphthol derivatives in the presence of triethylamine ...A variety of 2-arylnaphtho[ 1,2-d]oxazole derivatives were efficiently synthesized in moderate to high yields by the reaction of aromatic aldehydes with 1-amino-2-naphthol derivatives in the presence of triethylamine in refluxing ethanol in air. Seven new 2-arylnaphtho[1,2-d]oxazole derivatives were obtained and characterized by the spectral data and elemental analysis. In addition, the X-ray crystal structures of 2-[4-(N,N-dimethylamino)phenyl]naphtho[ 1,2-d] oxzole (3d) and 1, 1'-bis(naphtho[ 1,2-d]oxazol-2-yl)ferrocene (3n) have been determined.展开更多
Cp^*Co(Ⅲ)-catalyzed direct C—H amidation of azines has been developed.This co nversion could proceed smoothly in the absence of external oxidants,acids or bases,with excellent regioselectivity and broad functional g...Cp^*Co(Ⅲ)-catalyzed direct C—H amidation of azines has been developed.This co nversion could proceed smoothly in the absence of external oxidants,acids or bases,with excellent regioselectivity and broad functional group tolerance,CO2 was released as the sole byproduct,thus providing an environmentally benign amidation process.The products obtained are important intermediates in organic synthesis.展开更多
基金Supported by the Natural Science Foundation of Henan Province,China(No.0611012100).
文摘Ferrocenyliminophosphine 1 and 1,1′-bisferrocenyliminophosphine 2 were easily prepared from the condensation of formylferrocene or 1,1′-diformylferrocene with 2-(diphenylphosphino) aniline. The following reduction of imine group by LiAlH4 led to the formation of the corresponding ferrocenyl amidophosphines 3 and 4. The new ligands 2- 4 were well characterized by IR, ^1H NMR, ^31p NMR spectra, elemental analysis, and ESI-MS. The catalytic activity of all the ligands with palladium compounds in the Suzuki reaction was evaluated. Ligand 1, in combination with Pd (OAc)2, was found to be the most effective for the Suzuki reaction of aryl bromides with phenylboronic acid. Typically, the use of 0. 1% (molar fraction) of Pd(OAc)2/ligand 1 in the presence of two equivalents of K2CO3 as base in toluene at 110 ℃ provided good to excellent yields of the coupled products.
基金the National Natural Science Foundation of China (No. 20472074) the Natural Science Foundation of Henan Province (411020200) for financial support of this work.
文摘The new complexes, [PdCl{C5H4FeC5H4CHRN=CHC4H3O}(Ph3P)] (R= H, CH3) were synthesized via two novel Schiff bases (C5H5FeC5H4CHRN=CHC4H3O, R= H, CH3) with lithium tetrachloropalladate (Ⅱ), and characterized by IR, elemental analysis, ^1H NMR. Complex 5a was further determined by X-ray single crystal diffraction. We found that it contained an intramolecular N→Pd coordination in the compound 5a, and the palladium atom was bound to the unsubstituted Cp ring. The Pd-N, Pd-C (I) and Pd-O bond lengths were 2.121 (3), 2.008 (4) and 2.990 )A, respectively.
基金We acknowledge partial financial support from the Ministry of Science and Technology of China(No.2016YFE0132600)Henan Center for Outstanding Overseas Scientists(No.GZS2020001)and Zhengzhou University。
文摘A visible-light-promoted formal[2+2+1]cyclization of N-aryl glycines with quinoxalin-2(1H)-ones to synthesize tetrahydroimidazo[1,5-a]quinoxalin-4(5H)-ones have been developed.The protocol features operational simplicity,mild reaction conditions with blue LED light employing Ru(bpy)3Cl2.6H2O as a photoredox catalyst,a combination of O2 from air and Cu(OAc)2 as the oxidant and broad substrate applicability.
基金the National Natural Science Foundation of China (No. 20472074) The Innovation Fund for 0utstanding Scholar of Henan Province (No. 0621001100) for financial support.
文摘A series of europium(III) complexes with different chain length, tris [2-m-pyridylmethanamido-5-phenyl- (1,3,4)-oxadiazole] mono [2-(4-n-alkylphenyl)-iminazole (4,5-f)-1,10-phenanthroline] Eu(III) [Eu(PMA)3Nn (n = 6, 10, 14,18)] were synthesized. All of these amphiphilic europium(III) complexes could form stable Langmuir film at air/water interface and could be transferred onto hydrophilic quartz and mica substrates by measurement of UV spectra in which the absorbance of the LB films at about 288 nm scales showed the linearity with the number of layers deposited. In order to investigate relation between fluorescence properties and the arrangement of molecular in LB films, surface topography of monolayer films were observed by atomic force microscopy (AFM). Results showed that the emission spectra have Eu(III) characteristic peaks and strong emission strength. It is interesting that the molecular with looser arrangement in LB films has better monochromacity, which illustrated that energy might transferred more easily from ligand to Eu(III) in loosen structure films.
基金supported by the National Natural Science Foundation of China(21172200,21302172)the Basic Research Training Project of Zhengzhou University(JC2020053021)supported by the National Research Foundation of Korea(CRI Project No.2018R1A3B1052702 for Jong Seung Kim)。
文摘Achieving highly regioselective synthesis in organic chemistry is challenging due to the uncontrollable orientation between reacting partners.External electric fields(EEFs)can influence the reactivity and selectivity of the substrate by causing directional adsorption.However,scalable and efficient techniques for using EEFs as“smart catalysts”have been lacking,hindering their application.In this study,we present a novel method for modifying the regioselectivity of quinoxaline-2(1H)-ones by functionalizing their C7-position using the electric double layer(EDL)theory.This approach led to moderate to good yields of the corresponding C7-thiocyanation products.DFT calculations and control experiments demonstrated that EEFs could reverse the regioselectivity of quinoxaline-2(1H)-ones,allowing the C7-thiocyanation to proceed via a radical reaction mechanism.Additionally,the resulting 7-thiocyano-1-methylquinoxaline-2(1H)-ones exhibited promising AIE properties.Our work showcases a promising strategy for achieving highly regioselective functionalization by aligning the electric field with the desired reaction/bond axis.
基金financial support from the National Natural Science Foundation of China (No.21801087)Fundamental Research Funds for the Central Universities CCNU (No.CCNU19QN064)+2 种基金the Ministry of Science and Technology of China (No.2016YFE0132600)Henan Center for Outstanding Overseas Scientists (No.GZS2020001)the Key Scientific and Technological Project of Henan Province (No.212102311068)。
文摘Anthrones are key structural motifs in many natural products, bioactive compounds and pharmaceutical chemicals. Earth-abundant-metal-catalyzed asymmetric functionalization of anthrones has not proved to be viable. Herein, we disclosed a highly enantioselective propargylic substitution of anthrones with propargylic esters using copper salts with chiral N, N, P-ligand. This strategy is amenable to a broad range of substrates, uses readily available starting materials, provides excellent yields with remarkable enantioselectivity under mild conditions, and enables attractive products diversification routes.
基金partial financial support from the National Key R&D Program of China(No.2016YFE0132600)Henan Center for Outstanding Overseas Scientists(No.GZS2020001)Key Scientific and Technological Project of Henan Province(No.212102311068)。
文摘A Ru(Ⅲ)-catalyzed annulation reaction of 2-aminoaromatic aldehydes(ketones)and isoxazoles to afford diverse 3-cyanoquinolines has been developed.Notably,isoxazole acted as a cyclization reagent and nontoxic cyano source via N-O bond cleavage and fragmentation.Variously substituted(especially 6-or 7-substituted)quinolines could be easily afforded.This procedure features wide functional group compatibility,efficiency and avoiding toxic cyano source.Meanwhile,this protocol could be successfully applied to scale-up synthesis.Further chemical transformations of 3-cyanoquinoline could give some valuable skeletons,demonstrating its potential in synthetic application.
基金financially supported by the National Natural Science Foundation of China (No.21602046)the MOST of China (No.2016YFE0132600)the Doctor’s Scientific Research Foundation of Henan University of Chinese Medicine (No.BSJJ2016-12)
文摘The visible light promoted C-H sulfonylmethylation of imidazopyridines with easily accessible bromomethyl sulfones under mild reaction conditions was described.This protocol provides an effective and practical access to sulfonylmethylated imidazopyridines with good functional group tolerance.The desired products were provided in moderate to excellent yields for 50 examples at room temperature.The method could also be an attractive strategy to install a methyl group on imidazopyridines.
基金partial financial support from the Ministry of Science and Technology of China (No. 2016YFE0132600)Zhengzhou University
文摘Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.
基金partial financial support from the Ministry of Science and Technology of China(No.2016YFE0132600)Zhengzhou University。
文摘A selective ring-opening [3+2] cyclization reaction of benzo[d]isoxazoles with 2-bromo-propanamides has been developed.The azaoxyallyl cation intermediates are employed as C^O 3-atom synthon to build oxa-heterocycles via the selectivity of suitable cyclization partners.This transformation provides rapid access to highly functionalized 2-hydroxyaryl-oxazolines under mild conditions and excellent regioselectivity.
基金financial support from the Ministry of Science and Technology of China (No.2016YFE0132600)Henan Center for Outstanding Overseas Scientists (No.GZS2020001)Zhengzhou University。
文摘A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(Ⅲ)-catalyzed [4+2] annulation of N-arylbenzamidines with 1,4,2-dioxazol-5-ones.This reaction features excellent regioselectivity,broad substrate scope and high step economy,which would provide the refe rence for the construction of the fused 4-aminoquinazolines with biologically and pharmacologically active compounds.
基金financial support from the Ministry of Science and Technology of China (No.2016YFE0132600)Henan Center for Outstanding Overseas Scientists (No. GZS2020001)+1 种基金National Innovation and Entrepreneurship Training Program for College students (No.201910459064)Zhengzhou University
文摘A green tandem reaction,including insertion/aerobic oxidation/bisindolylation,starting from indoles and diazo compounds has been developed.The combination of water and fluorinated alcohol plays dual roles as solvent and promoter in this chemical transformation.Molecular oxygen in the air acts as an oxidant.3,3’-Bis(indolyl)methanes with quaternary carbon were produced under metal-free conditions.No any catalyst and additive were required.N2 and water were released as sole by-products.Absence of water and fluorinated alcohol resulted in Wolff rearrangement product.
文摘Due to using (R)- or (S)-a-methylbenzylamine as a chiral auxiliary, and low-temperature regime for reduction of the intermediate ferrocenyl-mono- or 1,1'-bis-ketimines, the corresponding secondary mono- or 1,1'-bis-amines were prepared with high diastereoselectivity. Removal of the a-methylbenzyl group afforded the optically active primary mono- and bis-ferrocenylethylamines in high yields. The absolute configuration of (R,R)-3a and (S,S)-3b was determined by X-ray single crystal diffraction.
基金Project supported by the National Natural Science Foundation of China (No. 20772114) and the Innovation Fund for Outstanding Scholar of Henan Province (No. 0621001100).
文摘An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. This chlori- nation was not a ligand-directed ortho-C--H activation, but an electrophilic substitution process at the para-position of the nitrogen atom in the benzo ring of benzoxazole moiety, the regiochemistry of which had been confirmed by HMBC spectral analysis. The catalytic system could tolerate various halogen atoms, such as F, Cl and Br, affording the corresponding products in moderate to excellent yields.
基金Project supported by the National Natural Science Foundation of China (No. 20472074) and the Innovation found for 0utstanding Scholars of Henan Province (No. 0621001100).
文摘A variety of 2-arylnaphtho[ 1,2-d]oxazole derivatives were efficiently synthesized in moderate to high yields by the reaction of aromatic aldehydes with 1-amino-2-naphthol derivatives in the presence of triethylamine in refluxing ethanol in air. Seven new 2-arylnaphtho[1,2-d]oxazole derivatives were obtained and characterized by the spectral data and elemental analysis. In addition, the X-ray crystal structures of 2-[4-(N,N-dimethylamino)phenyl]naphtho[ 1,2-d] oxzole (3d) and 1, 1'-bis(naphtho[ 1,2-d]oxazol-2-yl)ferrocene (3n) have been determined.
基金the Ministry of Science and Technology of China(No.2016YFE0132600)Henan Center for Outstanding Overseas Scientists(No.GZS2020001)。
文摘Cp^*Co(Ⅲ)-catalyzed direct C—H amidation of azines has been developed.This co nversion could proceed smoothly in the absence of external oxidants,acids or bases,with excellent regioselectivity and broad functional group tolerance,CO2 was released as the sole byproduct,thus providing an environmentally benign amidation process.The products obtained are important intermediates in organic synthesis.