Synthesis of symmetrical diaryl sulfoxides from arenes and thionyl chloride in the presence of a catalytic amount of iodine at room temperature under solvent-free conditions is described. Mild reaction conditions, eas...Synthesis of symmetrical diaryl sulfoxides from arenes and thionyl chloride in the presence of a catalytic amount of iodine at room temperature under solvent-free conditions is described. Mild reaction conditions, easy workup, high yield, and easily available catalyst are important features of this method.展开更多
（6-Amino-2-chloro-3-fluorophenyl）methanol is prepared through both traditional methods and palladium catalyzed iterative C–H halogenation reactions.In comparison to traditional approach,the C–H functionalization s...（6-Amino-2-chloro-3-fluorophenyl）methanol is prepared through both traditional methods and palladium catalyzed iterative C–H halogenation reactions.In comparison to traditional approach,the C–H functionalization strategy demonstrated a few advantages including milder reaction conditions higher yields,better selectivity and practicality,and high chemical diversity.展开更多
Polarfluorinated arenes can promote organic free radical reactions,which have attracted scientists’interest in recent years.However,it is still unknown how these solvents interact weakly with organic radical molecules...Polarfluorinated arenes can promote organic free radical reactions,which have attracted scientists’interest in recent years.However,it is still unknown how these solvents interact weakly with organic radical molecules to influence their reactiv-ity.In this study,we investigated how organic free radicals aggregate infive polarfluorocarbon solvents,and demonstrated that different substituents can influence their aggregation behaviors.In these solvents,small organic radicals with simple substituents maintain a homogeneous solution;however,radicals with substituents that form intermolecular hydrogen bonds or with long-chain aliphatic hydrocarbons tend to aggregate in them,whereas substituents of long-chain aliphatic hydrocar-bons tend to promote aggregation better.The critical aggregation concentrations of these aggregates are measured by concentration-dependent UV–visible spec-troscopy.Their topological morphologies are all spherical based on TEM.The compactness and rotational motivation speed of radical molecules within these aggregates are determined by EPR spectroscopy.The particle sizes of these aggre-gates are determined by analyzing their cyclic voltammograms.Most excitingly,electrochemical experiments reveal that the aggregation behaviors of free radical molecules with intermolecular hydrogen bonds can significantly increase their cat-alytic rate for electro-oxidizing benzyl alcohol in such a solvent.The results of this study indicate that in polarfluorinated arenes organic radical molecules’aggregation behaviors are related to their structures.This may provide guidelines for regulating organic radical reactivity in these solvents in the future.展开更多
Herein, a site-selective paired electrochemical C–H oxidation of functionalized alkyl arenes promoted by nickel catalyst is disclosed. A Ni(Ⅱ)-dioxygen species formed in situ efficiently enable the oxidation process...Herein, a site-selective paired electrochemical C–H oxidation of functionalized alkyl arenes promoted by nickel catalyst is disclosed. A Ni(Ⅱ)-dioxygen species formed in situ efficiently enable the oxidation process under mild conditions with a broad substrate scope with excellent functional group compatibilities,such as free carboxylic acid, aldehyde, halogen(including aryl iodide), amide and amino acid. The use of the nickel catalyst in combination with water provides a safe, green and economical method for oxidation of a range of molecules varying in complexity and drug derivatives, demonstrating its potential application in organic synthesis and the pharmaceutical industry. Reaction outcomes and mechanistic studies revealed the key role of the in situ Ni(Ⅱ)-dioxygen species for the subsequent oxidation of C(sp^(3))–H bonds,and short-lived reactive intermediates(aryl radical cation) was rapidly captured by the combination of a bipolar ultramicroelectrode(BUME) with nano-electrospray ionization mass spectrometry.展开更多
By virtue of the atom-and step-economy, utilization of simple arenes as a supplant of pre-prepared aryl metal species or aryl halides for the synthesis of arylated chiral molecules has attracted great attention from t...By virtue of the atom-and step-economy, utilization of simple arenes as a supplant of pre-prepared aryl metal species or aryl halides for the synthesis of arylated chiral molecules has attracted great attention from the synthetic community. While transition-metal-catalyzed enantioselective diarylation of tethered alkenes has been employed to prepare important chiral cyclic compounds, the direct use of simple arenes as aryl precursors is still underdeveloped, probably due to the difficulties in the effective control of the reactivity, site-selectivity and/or enantioselectivity. Herein we report an asymmetric Pd/Ag dual metal catalytic system for the non-directed, site-and enantioselective domino Heck/intermolecular C–H functionalization of arenes.Mechanistic studies showed that Pd and Ag act in cooperation in the catalysis and the chiral bisphosphine ligand plays a bifunctional role, i.e., assisting the silver species in the cleavage of the aryl C–H bond, while inducing the enantioselectivity on direct complexation with palladium. This method provides an efficient approach to the corresponding chiral oxindoles with good enantiomeric excesses from a broad scope of arenes, including fluoroarenes, heteroarenes and several complex products derived from medicines or natural products.展开更多
A ligand-free nickel-catalyzed Kumada cross-coupling of aryl bromides and tert-butyl Grignard reagents led to the formation of a series of tert-butyl aryls in moderate to good yields, excellent tBu/iBu ratios, and goo...A ligand-free nickel-catalyzed Kumada cross-coupling of aryl bromides and tert-butyl Grignard reagents led to the formation of a series of tert-butyl aryls in moderate to good yields, excellent tBu/iBu ratios, and good functional group compatibility. A radical coupling process is indicated and a mechanism with a Ni(Ⅰ)-Ni(Ⅲ) catalytic cycle is proposed.展开更多
25,27-bis-(2-aminoethoxy)-p-tert-butylcalix[4]arene was linked to double calix[4]arene derivatives by the Schiff-base moiety in its lower rim. They behave strong ability to complex with Ph2+, Cu2+ and Co2+.
The extraction residue from Shengli lignite was sequentially dissolved in cyclohexane, benzene, methanol, ethanol, and isopropanol in an autoclave at 320℃ to afford soluble portions(SPs) 1–5(SP_1-SP_5) and the final...The extraction residue from Shengli lignite was sequentially dissolved in cyclohexane, benzene, methanol, ethanol, and isopropanol in an autoclave at 320℃ to afford soluble portions(SPs) 1–5(SP_1-SP_5) and the final residue(FR). The total yield of SP_1-SP_5 is ca. 55.1%. The FR was subjected to ruthenium ioncatalyzed oxidation and the resulting products were isolated from the reaction mixture and esterified.Both the esterified products and SP_1-SP_5 were analyzed with a gas chromatograph/mass spectrometer.In total, 342 compounds were identified in SP_1-SP_5. They can be classified into normal alkanes, branched alkanes, alkenes, alkanedienes, arenes, alkanols, methylcycloalkanes, alkenols, alkylbenzenemethanols,arenols, anisol and substituted anisols, polymethyldihydrobenzofurans, arenofurans, dibenzofurans,ethoxymethylbenzenes, aldehydes, ketones, esters, nitrogen-containing organic compounds, sulfurcontaining organic compounds, and other compounds. Among the compounds, arenols are predominant in SP_1 and SP_2 and the main compounds in SP_3, while the main compounds in SP_4 and SP_5 are esters and arenes, respectively. According to the esterified products identified, the products from the FR oxidation can be grouped into non-benzene ring carboxylic acids(NBCAs) and benzenepolycarboxylic acids(BPCAs). The total yield of BPCAs is much higher than that of NBCAs, suggesting that the FR is rich in condensed aromatic moieties.展开更多
An efficient BF3.OEt2-promoted benzylation of arenes and heteroarenes with various benzyl ether derivatives has been developed. This method provided alternative access to valuable diarylmethane in good yields under mi...An efficient BF3.OEt2-promoted benzylation of arenes and heteroarenes with various benzyl ether derivatives has been developed. This method provided alternative access to valuable diarylmethane in good yields under mild conditions via an easy work-up procedure.展开更多
A novel copper-catalyzed direct C–N formation reaction of simple arenes with cheap and pharmacological saccharin derivatives under relatively mild conditions was developed with arenes as limiting reagents.This work p...A novel copper-catalyzed direct C–N formation reaction of simple arenes with cheap and pharmacological saccharin derivatives under relatively mild conditions was developed with arenes as limiting reagents.This work provided a new method for oxidative coupling of aromatic C(sp2)–H bonds and N–H bonds.展开更多
A new method employing magnetic nanoparticles Fe3O4 as a catalyst and H2O2 as a green oxidant is developed for the oxidative thiocyanation of aromatic amines, anisols and activated phenols with high yields under mild ...A new method employing magnetic nanoparticles Fe3O4 as a catalyst and H2O2 as a green oxidant is developed for the oxidative thiocyanation of aromatic amines, anisols and activated phenols with high yields under mild reaction conditions. The catalyst could be easily recovered from the reaction mixture using an external magnet and reused in several reaction cycles without loss of activity.展开更多
文摘Synthesis of symmetrical diaryl sulfoxides from arenes and thionyl chloride in the presence of a catalytic amount of iodine at room temperature under solvent-free conditions is described. Mild reaction conditions, easy workup, high yield, and easily available catalyst are important features of this method.
基金supported by ‘973’ Project (No. 2011CB965300)NSFC (Nos. 21142008, 21302106)+1 种基金Tsinghua University 985 Phase II Fundsthe Tsinghua University Initiative Scientific Research Program
文摘（6-Amino-2-chloro-3-fluorophenyl）methanol is prepared through both traditional methods and palladium catalyzed iterative C–H halogenation reactions.In comparison to traditional approach,the C–H functionalization strategy demonstrated a few advantages including milder reaction conditions higher yields,better selectivity and practicality,and high chemical diversity.
基金National Natural Science Foundation of China,Grant/Award Numbers:22171141,22193010,22193014Fundamental Research Funds for the Central Universities,Grant/Award Number:020–63233022。
文摘Polarfluorinated arenes can promote organic free radical reactions,which have attracted scientists’interest in recent years.However,it is still unknown how these solvents interact weakly with organic radical molecules to influence their reactiv-ity.In this study,we investigated how organic free radicals aggregate infive polarfluorocarbon solvents,and demonstrated that different substituents can influence their aggregation behaviors.In these solvents,small organic radicals with simple substituents maintain a homogeneous solution;however,radicals with substituents that form intermolecular hydrogen bonds or with long-chain aliphatic hydrocarbons tend to aggregate in them,whereas substituents of long-chain aliphatic hydrocar-bons tend to promote aggregation better.The critical aggregation concentrations of these aggregates are measured by concentration-dependent UV–visible spec-troscopy.Their topological morphologies are all spherical based on TEM.The compactness and rotational motivation speed of radical molecules within these aggregates are determined by EPR spectroscopy.The particle sizes of these aggre-gates are determined by analyzing their cyclic voltammograms.Most excitingly,electrochemical experiments reveal that the aggregation behaviors of free radical molecules with intermolecular hydrogen bonds can significantly increase their cat-alytic rate for electro-oxidizing benzyl alcohol in such a solvent.The results of this study indicate that in polarfluorinated arenes organic radical molecules’aggregation behaviors are related to their structures.This may provide guidelines for regulating organic radical reactivity in these solvents in the future.
基金Financial support from National Key R&D Program of China(No.2022YFA1503200)National Natural Science Foundation of China(No.22188101)+1 种基金the Fundamental Research Funds for the Central Universities(No.63223007)Frontiers Science Center for New Organic Matter,Nankai University(No.63181206)and Nankai University.
文摘Herein, a site-selective paired electrochemical C–H oxidation of functionalized alkyl arenes promoted by nickel catalyst is disclosed. A Ni(Ⅱ)-dioxygen species formed in situ efficiently enable the oxidation process under mild conditions with a broad substrate scope with excellent functional group compatibilities,such as free carboxylic acid, aldehyde, halogen(including aryl iodide), amide and amino acid. The use of the nickel catalyst in combination with water provides a safe, green and economical method for oxidation of a range of molecules varying in complexity and drug derivatives, demonstrating its potential application in organic synthesis and the pharmaceutical industry. Reaction outcomes and mechanistic studies revealed the key role of the in situ Ni(Ⅱ)-dioxygen species for the subsequent oxidation of C(sp^(3))–H bonds,and short-lived reactive intermediates(aryl radical cation) was rapidly captured by the combination of a bipolar ultramicroelectrode(BUME) with nano-electrospray ionization mass spectrometry.
基金supported by the National Key R&D Program of China (2021YFA1500100)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB0610000)+2 种基金the National Natural Science Foundation of China (92256303, 22171278, 21821002)the Shanghai Science and Technology Committee (23ZR1482400)the Natural Science Foundation of Ningbo (2023J034)。
文摘By virtue of the atom-and step-economy, utilization of simple arenes as a supplant of pre-prepared aryl metal species or aryl halides for the synthesis of arylated chiral molecules has attracted great attention from the synthetic community. While transition-metal-catalyzed enantioselective diarylation of tethered alkenes has been employed to prepare important chiral cyclic compounds, the direct use of simple arenes as aryl precursors is still underdeveloped, probably due to the difficulties in the effective control of the reactivity, site-selectivity and/or enantioselectivity. Herein we report an asymmetric Pd/Ag dual metal catalytic system for the non-directed, site-and enantioselective domino Heck/intermolecular C–H functionalization of arenes.Mechanistic studies showed that Pd and Ag act in cooperation in the catalysis and the chiral bisphosphine ligand plays a bifunctional role, i.e., assisting the silver species in the cleavage of the aryl C–H bond, while inducing the enantioselectivity on direct complexation with palladium. This method provides an efficient approach to the corresponding chiral oxindoles with good enantiomeric excesses from a broad scope of arenes, including fluoroarenes, heteroarenes and several complex products derived from medicines or natural products.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No. XDB20000000)CAS (No. QYZDY-SSW-SLH029)+2 种基金National Natural Science Foundation of China (Nos. 21725205, 21432007, 21572246)STCSM18520712200K.C. Wong Education Foundation
文摘A ligand-free nickel-catalyzed Kumada cross-coupling of aryl bromides and tert-butyl Grignard reagents led to the formation of a series of tert-butyl aryls in moderate to good yields, excellent tBu/iBu ratios, and good functional group compatibility. A radical coupling process is indicated and a mechanism with a Ni(Ⅰ)-Ni(Ⅲ) catalytic cycle is proposed.
文摘25,27-bis-(2-aminoethoxy)-p-tert-butylcalix[4]arene was linked to double calix[4]arene derivatives by the Schiff-base moiety in its lower rim. They behave strong ability to complex with Ph2+, Cu2+ and Co2+.
基金provided by the Key Project of Joint Fund from National Natural Science Foundation of Chinathe Government of Xinjiang Uygur Autonomous Region (Grant U1503293)+1 种基金Natural Scientific Foundation of China (Grant 21576280)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The extraction residue from Shengli lignite was sequentially dissolved in cyclohexane, benzene, methanol, ethanol, and isopropanol in an autoclave at 320℃ to afford soluble portions(SPs) 1–5(SP_1-SP_5) and the final residue(FR). The total yield of SP_1-SP_5 is ca. 55.1%. The FR was subjected to ruthenium ioncatalyzed oxidation and the resulting products were isolated from the reaction mixture and esterified.Both the esterified products and SP_1-SP_5 were analyzed with a gas chromatograph/mass spectrometer.In total, 342 compounds were identified in SP_1-SP_5. They can be classified into normal alkanes, branched alkanes, alkenes, alkanedienes, arenes, alkanols, methylcycloalkanes, alkenols, alkylbenzenemethanols,arenols, anisol and substituted anisols, polymethyldihydrobenzofurans, arenofurans, dibenzofurans,ethoxymethylbenzenes, aldehydes, ketones, esters, nitrogen-containing organic compounds, sulfurcontaining organic compounds, and other compounds. Among the compounds, arenols are predominant in SP_1 and SP_2 and the main compounds in SP_3, while the main compounds in SP_4 and SP_5 are esters and arenes, respectively. According to the esterified products identified, the products from the FR oxidation can be grouped into non-benzene ring carboxylic acids(NBCAs) and benzenepolycarboxylic acids(BPCAs). The total yield of BPCAs is much higher than that of NBCAs, suggesting that the FR is rich in condensed aromatic moieties.
文摘An efficient BF3.OEt2-promoted benzylation of arenes and heteroarenes with various benzyl ether derivatives has been developed. This method provided alternative access to valuable diarylmethane in good yields under mild conditions via an easy work-up procedure.
基金financially supported by the National Natural Science Foundation of China(21172033,21372041,21302017)
文摘A novel copper-catalyzed direct C–N formation reaction of simple arenes with cheap and pharmacological saccharin derivatives under relatively mild conditions was developed with arenes as limiting reagents.This work provided a new method for oxidative coupling of aromatic C(sp2)–H bonds and N–H bonds.
基金financial support of this study by Shiraz University Research Council
文摘A new method employing magnetic nanoparticles Fe3O4 as a catalyst and H2O2 as a green oxidant is developed for the oxidative thiocyanation of aromatic amines, anisols and activated phenols with high yields under mild reaction conditions. The catalyst could be easily recovered from the reaction mixture using an external magnet and reused in several reaction cycles without loss of activity.
