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Acceptorless dehydrogenative amination of alkenes for the synthesis of N-heterocycles

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Science China chemistry 2022年第7期65卷 1330-1337页

作者： Jia-Lin Tu Wan Tang Shi-Hui He Ma Su Feng Liu Jiangsu Key laboratory of Neuropsychiatric Diseases and Department of medicinal chemistry College of Pharmaceutical SciencesSoochow UniversitySuzhou 215123China Key laboratory of Organofluorine chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Catalytic amination of alkenes is one of the most attractive reactions for the construction of complex heterocycles with nitrogen centers. Herein, we present that synergistic photoredox and cobaloxime catalysis allows for highly efficient and mild dehydrogenative reactions between various NH nucleophiles and di-, tri-, and tetrasubstituted alkenes in the absence of external oxidants, thus enabling access to an array of N-heterocycles. Notably, both Z-and E-alkene-containing N-heterocycles are accessible. Mechanistic studies indicated that the Z-cinnamyl derivatives could be generated by photocatalytic E to Z alkene isomerization through an energy transfer process. Moreover, we find that sluggish energy transfer could inhibit the E to Z alkene isomerization process, thus offering the cinnamyl derivatives with E-selectivity. Our results highlight the benefits of the reactions using dual photoredox and cobaloxime catalysis to lead to diverse N-heterocycles.

关键词： nitrogen-centered radical alkene amination photoredox cyclization N-heterocycle

From aniline to phenol: carbon-nitrogen bond activation via uranyl photoredox catalysis

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National Science Review 2022年第6期9卷 74-80页

作者： Deqing Hu Yilin Zhou Xuefeng Jiang Shanghai Key laboratory of Green chemistry and Chemical Process School of Chemistry and Molecular Engineering East China Normal University State Key laboratory of Organometallic chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences State Key laboratory of Elemento-organic chemistry Nankai University

Carbon-nitrogen bond activation, via uranyl photoredox catalysis with water, enabled the conversion of 40 protogenetic anilines, 8 N-substituted anilines and 9 aniline-containing natural products/pharmaceuticals to the corresponding phenols in an ambient environment. A single-electron transfer process between a protonated aniline and uranyl catalyst, which was disclosed by radical quenching experiments and Stern-Volmer analysis, facilitated the following oxygen atom transfer process between the radical cation of protonated anilines and uranyl peroxide originating from water-splitting.18O labeling and15N tracking unambiguously depicted that the oxygen came from water and amino group left as ammonium salt. The 100-fold efficiency of the flow operation demonstrated the great potential of the conversion process for industrial synthetic application.

关键词： C−N bond activation C−O bond formation uranyl cations photoredox catalysis

A general method for one-step synthesis of monofluoroiodane(Ⅲ)reagents using silver difluoride

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Chinese Chemical Letters 2022年第11期33卷 4834-4837页

作者： Jing Ren Meng-Cheng Jia Feng-Huan Du Chi Zhang State Key laboratory of Elemento-organic chemistry The Research Institute of Elemento-Organic ChemistryCollege of ChemistryNankai UniversityTianjin 300071China

Herein we report a new general method for one-step synthesis of four kinds of fluoroiodane(Ⅲ)reagents by treating the corresponding aryl iodides with silver difluoride(AgF_(2)).This is the first method applicable for the synthesis of all four fluoroiodane(Ⅲ)reagents including p-iodotoluene difluoride(1),fluoro-benziodoxole(2),fluoro-benziodoxolone(3),and fluoro-N-acetylbenziodazole(4).AgF_(2)was firstly employed in the direct oxidative fluorination of iodobenzene and thus has shown its outstanding oxidation and fluorine-transfer ability.The use of AgF_(2)has improved the synthesis of fluoroiodane(Ⅲ)reagents by shortening the reaction steps,avoiding the use of hazardous reagents,and simplifying the experimental operations.It was worth noting that we have developed the first one-step direct synthetic method for 3,while 3 can only be synthesized through Cl→F ligand exchange reaction previously.

关键词： Monofluoroiodane(Ⅲ)reagents Silver difluoride Iodobenzene derivatives One-step synthesis DFT calculations

Synthesis of 2-Deoxy-C-Glycosides via Iridium-Catalyzed sp^(2)and sp^(3)C-H Glycosylation with Unfunctionalized Glycals

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Chinese Journal of chemistry 2022年第5期40卷 571-576页

作者： Wanjun Zhu Qikai Sun Hai Chang Hui-Xing Zhang Quanquan Wang Gong Chen Gang He State Key laboratory and institute of Elemento-organic chemistry College of ChemistryNankai UniversityTianjin300071 China

A new protocol for the synthesis of 2-deoxy-C-aryl-glycosides and 2-deoxy-C-alkyl-glycosides via iridium-catalyzed directed C—H glycosylation with glycals is reported.The method is amenable for both the C_(2)C—H glycosylation of indoles and the methyl C—H glycosylation of secondary methyl amines under the control of an N-linked benzoxazole directing group.The benzoxazole group can be cleanly removed by the treatment of KOH or LiAlH_(4).

关键词： 2-Deoxy-C-glycoside Iridium C-Hactivation Glycosylation Glycals

Palladium-Catalyzed Skeletal Reorganization of Cyclobutanones Invoving Successive C—C Bond/C—H Bond Cleavage

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中国化学:英文版 2023年第14期41卷 1679-1683页

作者： Ruirui Li Xiaonan Shi Dongbing Zhao State Key laboratory and institute of Elemento-organic chemistry College of ChemistryNankai UniversityTianjin300071 China

The utilization of cyclobutanones as the synthon in transition metal catalysis has been made great success.Because C(carbonyl)−C bond of cyclobutanones can be cleaved through strain release.Despite those advancements,the main catalysts in literature are Rh catalysts or Ni catalysts and the reaction with C—H bond is still underdeveloped.Herein,we realized the first palladium-catalyzed skeletal reorganization of cyclobutanones involving successive cleavage of C(carbonyl)−C bonds and C—H bond cleavage,which constitutes an rapid access to diverse indanones.In contrast to the previous Rh-catalytic system,the Pd-catalytic system herein involves different mechanism and features several advantages:1)no need of directing group to facilitate the C(carbonyl)−C bond cleavage;2)much milder reaction condition and 3)simplified work-up.

关键词： Cyclobutanones C-C activation C-H activation Palladium catalysis Ring expansion

Iron-Catalyzed Alkenylzincation of Internal Alkynes

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Chinese Journal of chemistry 2023年第24期41卷 3547-3552页

作者： Wei-Na Wang Qiang Huang Ye Jin Qi-Lin Zhou Shou-Fei Zhu Frontiers Science Center for New organic Matter State Key Laboratory and Institute of Elemento-Organic ChemistryCollege of ChemistryNankai UniversityTianjin300071 China

The alkenylzincation of internal alkynes is an effective method for the synthesis of multi-substituted conjugated dienes;however,the current catalytic systems for this reaction are limited in terms of substrate scope and selectivity control,which restricts its practical applications.Herein,we report the first iron-catalyzed alkenylzincation of internal alkynes,which features mild conditions,simple operation,broad substrate scope (including aryl/alkyl,diaryl,and dialkyl acetylenes),excellent functional group tolerance (tolerating highly active functional groups such as ester,methylthio,amide,sulfonyl,cyano,etc.),and high activity (with a turnover number of up to 11500,the highest record for carbometallation reactions).Notably,the catalytic system described in this article also realized the highly selective vinylzincation of unfunctionalized internal alkynes as well as the alkenylzincation of unsymmetrical diarylacetylenes and dialkyl acetylenes,which have not been achieved with other catalytic systems reported in the literatures.The current study provides a highly selective access to synthetically important multi-substituted conjugated dienes.

关键词： Iron catalysis Internal alkynes Alkenylzincation Conjugated dienes

Electro-reductive C-H cyanoalkylation of quinoxalin-2(1H)-ones

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Chinese Chemical Letters 2022年第8期33卷 4057-4060页

作者： Ling Ding Kaikai Niu Yuxiu Liu Qingmin Wang State Key laboratory of Elemento-organic chemistry Research Institute of Elemento-Organic ChemistryCollege of ChemistryFrontiers Science Center for New Organic MatterNankai UniversityTianjin 300071China

Herein,we report a practical electro-reductive protocol for the direct C-H cyanoalkylation of quinoxalin-2(1 H)-ones via iminyl radical-mediated ring opening.These mild reactions proceed under metal-,reductant-,and re... 详细信息

关键词： Electro-reductive C-H cyanoalkylation Reductant-free Quinoxalin-2(1H)-ones Ring-opening

Rhodium-catalyzed enantioselective annulation of N-phenoxyacetamides with 1,3-dienes

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Science China chemistry 2023年第10期66卷 2842-2846页

作者： Hui Yang Zi-Qi Yang Su-Zhen Zhang Wen-Wen Zhang Qing Gu Shu-Li You State Key laboratory of Organometallic chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Chiral dihydrobenzofuran is a valuable synthetic fragment in both medicinal and organic chemistry.Efficient rhodium(Ⅲ)-catalyzed chemoselective and enantioselective C-H functionalization/[3+2]annulation of N-phenoxyacetamides with 1,3-dienes is reported.In the presence of 5 mol%Cp Rh complex,various chiral dihydrobenzofurans were synthesized in up to 79%yield and 98%ee.This reaction proceeds under mild conditions with excellent functional group compatibility.

关键词： asymmetric catalysis C-H functionalization rhodium catalysis chiral dihydrobenzofuran

Divergent synthesis of aryl amines and dihydroquinazolinones via electrochemistry-enabled rhodium-catalyzed C–H functionalization

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中国科学:化学英文版 2023年第10期66卷 2863-2870页

作者： Yi-Kang Xing Zhen-Hua Wang Ping Fang Cong Ma Tian-Sheng Mei State Key laboratory of Organometallic chemistry Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesShanghai 200032China

Electrochemistry-enabled rhodium-catalyzed C–H amination and amination cyclization of arene assisted by a weakly coordinating amide have been reported. Additionally, aryl amines and dihydroquinazolinones could be obtained selectively by controlling the electric current. Mechanistic studies suggested that the amination reaction likely involves an electrochemical oxidation-induced reductive elimination of a high valent rhodium intermediate, which led to the amination reaction even proceeding smoothly at room temperature.

关键词： organic electrochemistry rhodium catalysis C-H functionalization divergent synthesis