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1.
Yichu Liu Yibing Wang Wenhao Dai Wei Huang Yingxia Li Hong Liu 《Angewandte Chemie (International ed. in English)》2020,59(9):3491-3494
We have developed a highly efficient and practical approach for palladium‐catalyzed trifluoroacetate‐promoted N‐quinolylcarboxamide‐directed glycosylation of inert β‐C(sp3)?H bonds of N‐phthaloyl α‐amino acids with glycals under mild conditions. For the first time, C(sp3)?H activation for glycosylation was achieved to build C‐alkyl glycosides. This method facilitates the synthesis of various β‐substituted C‐alkyl glycoamino acids and offers a tool for glycopeptide synthesis. 相似文献
2.
MnI/AgI Relay Catalysis: Traceless Diazo‐Assisted C(sp2)–H/C(sp3)–H Coupling to β‐(Hetero)Aryl/Alkenyl Ketones
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Dr. Qingquan Lu Shobhan Mondal Dr. Sara Cembellín Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2018,57(33):10732-10736
An unprecedented MnI/AgI‐relay‐catalyzed C(sp2)?H/C(sp3)?H coupling of (vinyl)arenes with α‐diazoketones is reported, wherein the diazo group was exploited as a traceless auxiliary for control of regioselectivity. Challenging β‐(hetero)aryl/alkenyl ketones were obtained through this operationally simple approach. The cascade process merges denitrogenation, carbene rearrangement, C?H activation, and hydroarylation/hydroalkenylation. The robustness of this method was demonstrated at preparative scale and applied to late‐stage diversification of natural products. 相似文献
3.
Robert Szpera Daniel F. J. Moseley Lewis B. Smith Alistair J. Sterling Vronique Gouverneur 《Angewandte Chemie (International ed. in English)》2019,58(42):14824-14848
This Review summarizes advances in fluorination by C(sp2)?H and C(sp3)?H activation. Transition‐metal‐catalyzed approaches championed by palladium have allowed the installation of a fluorine substituent at C(sp2) and C(sp3) sites, exploiting the reactivity of high‐oxidation‐state transition‐metal fluoride complexes combined with the use of directing groups (some transient) to control site and stereoselectivity. The large majority of known methods employ electrophilic fluorination reagents, but methods combining a nucleophilic fluoride source with an oxidant have appeared. External ligands have proven to be effective for C(sp3)?H fluorination directed by weakly coordinating auxiliaries, thereby enabling control over reactivity. Methods relying on the formation of radical intermediates are complementary to transition‐metal‐catalyzed processes as they allow for undirected C(sp3)?H fluorination. To date, radical C?H fluorinations mainly employ electrophilic N?F fluorination reagents but a unique MnIII‐catalyzed oxidative C?H fluorination using fluoride has been developed. Overall, the field of late‐stage nucleophilic C?H fluorination has progressed much more slowly, a state of play explaining why C?H 18F‐fluorination is still in its infancy. 相似文献
4.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(25):7324-7328
A general and user‐friendly synthesis of β‐lactams is reported that makes use of Pd0‐catalyzed carbamoylation of C(sp3)−H bonds, and operates under stoichiometric carbon monoxide in a two‐chamber reactor. This reaction is compatible with a range of primary, secondary and activated tertiary C−H bonds, in contrast to previous methods based on C(sp3)−H activation. In addition, the feasibility of an enantioselective version using a chiral phosphonite ligand is demonstrated. Finally, this method can be employed to synthesize valuable enantiopure free β‐lactams and β‐amino acids. 相似文献
5.
Wei Wang Dr. Mélanie M. Lorion Oscar Martinazzoli Prof. Dr. Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2018,57(33):10554-10558
Late‐stage BODIPY diversification of structurally complex amino acids and peptides was accomplished by racemization‐free palladium‐catalyzed C(sp3)?H activation. Transformative fluorescence modification proved viable by triazole‐assisted C(sp3)?H arylation in a chemo‐ and site‐selective fashion, providing modular access to novel BODIPY peptide sensors. 相似文献
6.
Dr. Xuesong Wu Yan Zhao Prof. Dr. Haibo Ge 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(31):9530-9533
Intramolecular dehydrogenative cyclization of aliphatic amides was achieved on unactivated sp3 carbon atoms by a nickel‐catalyzed C?H bond functionalization process with the assistance of a bidentate directing group. The reaction favors the C?H bonds of β‐methyl groups over the γ‐methyl or β‐methylene groups. Additionally, a predominant preference for the β‐methyl C?H bonds over the aromatic sp2 C?H bonds was observed. Moreover, this process also allows for the effective functionalization of benzylic secondary sp3 C?H bonds. 相似文献
7.
Ailan Lu Xiaoming Ji Bo Zhou Zhuo Wu Prof. Dr. Yanghui Zhang 《Angewandte Chemie (International ed. in English)》2018,57(12):3233-3237
A highly efficient palladium‐catalyzed disilylation reaction of aryl halides through C?H activation has been developed for the first time. The reaction has broad substrate scope. A variety of aryl halides can be disilylated by three types of C?H activation, including C(sp2)?H, C(sp3)?H, and remote C?H activation. In particular, the reactions are also unusually efficient. The yields are essentially quantitative in many cases, even in the presence of less than 1 mol % catalyst and 1 equivalent of the silylating reagent under relatively mild conditions. The disilylated biphenyls can be converted into disiloxane‐bridged biphenyls. 相似文献
8.
Dr. Suhua Li Ru‐Yi Zhu Dr. Kai‐Jiong Xiao Prof. Dr. Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2016,55(13):4317-4321
PdII‐catalyzed arylation of γ‐C(sp3)?H bonds of aliphatic acid‐derived amides was developed by using quinoline‐based ligands. Various γ‐aryl‐α‐amino acids were prepared from natural amino acids using this method. The influence of ligand structure on reactivity was also systematically investigated. 相似文献
9.
Lijun Lu Renyi Shi Luyao Liu Jingwen Yan Fangling Lu Prof. Aiwen Lei 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14484-14488
Directly utilizing a chemical feedstock to construct valuable compounds is an attractive prospect in organic synthesis. In particular, the combination of C(sp3)?H activation and oxidative carbonylation involving alkanes and CO gas is a promising and efficient method to synthesize carbonyl derivatives. However, due to the high C?H bond dissociation energy and low polarity of unactivated alkanes, the carbonylation of unactivated C(sp3)?H bonds still remains a great challenge. In this work, we introduce a palladium‐catalyzed radical oxidative alkoxycarbonylation of alkanes to prepare numerous alkyl carboxylates. Various alkanes and alcohols were compatible, generating the desired products in up to 94 % yield. Remarkably, ethane, a constituent of natural gas, could be employed as a substrate under the standard reaction conditions. Preliminary mechanistic studies revealed a probable palladium‐catalyzed radical process. 相似文献
10.
Radical Cation Salt‐initiated Aerobic C−H Phosphorylation of N‐Benzylanilines: Synthesis of α‐Aminophosphonates
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Prof. Xiaodong Jia Xiaofei Liu Prof. Yu Yuan Pengfei Li Wentao Hou Kaixuan He 《化学:亚洲杂志》2018,13(15):1911-1914
A radical cation salt‐initiated phosphorylation of N‐benzylanilines was realized through an aerobic oxidation of the sp3 C?H bond, providing a series of α‐aminophosphonates in high yields. An investigation of the reaction scope revealed that this mild catalyst system is superior in good functional group tolerance and high reaction efficiency. The mechanistic study implied that the cleavage of the sp3 C?H bond was involved in the rate‐determining step. 相似文献
11.
Alkenylation of C(sp3)−H Bonds by Zincation/Copper‐Catalyzed Cross‐Coupling with Iodonium Salts
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Dr. Chuan Liu Prof. Dr. Qiu Wang 《Angewandte Chemie (International ed. in English)》2018,57(17):4727-4731
α‐Vinylation of phosphonates, phosphine oxides, sulfones, sulfonamides, and sulfoxides has been achieved by selective C?H zincation and copper‐catalyzed C(sp3)?C(sp2) cross‐coupling reaction using vinylphenyliodonium salts. The vinylation transformation proceeds in high efficiency and stereospecificity under mild reaction conditions. This zincative cross‐coupling reaction represents a general alkenylation strategy, which is also applicable for α‐alkenylation of esters, amides, and nitriles in the synthesis of β,γ‐unsaturated carbonyl compounds. 相似文献
12.
Theoretical investigation toward organophosphine‐catalyzed [3 + 3] annulation of Morita–Baylis–Hillman carbonates with azomethine imines: Mechanism,origin of stereoselectivity,and role of catalyst
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Wei Zhang Yan Qiao Yang Wang Mingsheng Tang Donghui Wei 《International journal of quantum chemistry》2017,117(11)
A computational study on the detailed mechanism and stereoselectivity of the chiral phosphine‐catalyzed C(sp2)? H activation/[3 + 3] annulation between Morita–Baylis–Hillman (MBH) carbonates and C,N‐cyclic azomethine imines has been performed. Generally, the catalytic cycle consists of two stages, that is, C(sp2)? H activation companied by the dissociation of the t‐BuO group forming phosphonium enolate, and [3 + 3] cycloaddition process followed by regeneration of the catalyst. The calculated results indicate that C(sp2)? H activation is rate‐determining while [3 + 3] cycloaddition is stereoselectivity‐determining. Furthermore, the advantageous hydrogen bond interactions and less steric hindrance in the RR configurational C? C bond forming transition states should be responsible for the favorability of RR‐configured product among the four possible products. The special role of the organocatalyst was also identified by natural bond orbital (NBO) and global reactivity index (GRI) analyses. The mechanistic insights obtained in the present study should be useful for understanding the novel organocatalytic C(sp2)? H activation and cycloaddition cascade reaction of MBH carbonates, and thus provide valuable clues on rational design of efficient organocatalysts for the C(sp2)? H activation/functionalizations. 相似文献
13.
Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation,Hydrogen Atom Transfer,and Carbene/Nitrene Transfer
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John C. K. Chu Prof. Tomislav Rovis 《Angewandte Chemie (International ed. in English)》2018,57(1):62-101
The functionalization of C(sp3)?H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C?H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition‐metal‐catalyzed C?H activation, 1,n‐hydrogen atom transfer, and transition‐metal‐catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp3)?H bonds. For each strategy, the scope, the reactivity of different C?H bonds, the position of the reacting C?H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C?H functionalization reactions and inspire future research in this area. 相似文献
14.
Intermolecular Amination of Unactivated C(sp3)−H Bonds with Cyclic Alkylamines: Formation of C(sp3)−N Bonds through Copper/Oxygen‐Mediated C(sp3)−H/N−H Activation
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Quan Gou Yu‐Wen Yang Zi‐Ning Liu Prof. Jun Qin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(45):16057-16061
The first example of intermolecular amination of unactivated C(sp3)?H bonds by cyclic alkylamines mediated by Cu(OAc)2/O2 is reported. This method avoids the use of benzoyloxyamines as the aminating reagent, which are normally prepared from alkylamines in extra steps. A variety of unnatural β2, 2‐amino acid analogues are synthesized by this simple and efficient procedure. This approach offers a solution to the previous unmet challenge of C(sp3)?H/N?H activation for the formation of C(sp3)?N bonds. 相似文献
15.
Continuous‐Flow Synthesis and Derivatization of Aziridines through Palladium‐Catalyzed C(sp3)−H Activation
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Jacek Zakrzewski Adam P. Smalley Dr. Mikhail A. Kabeshov Prof. Matthew J. Gaunt Prof. Alexei A. Lapkin 《Angewandte Chemie (International ed. in English)》2016,55(31):8878-8883
A continuous‐flow synthesis of aziridines by palladium‐catalyzed C(sp3)?H activation is described. The new flow reaction could be combined with an aziridine‐ring‐opening reaction to give highly functionalized aliphatic amines through a consecutive process. A predictive mechanistic model was developed and used to design the C?H activation flow process and illustrates an approach towards first‐principles design based on novel catalytic reactions. 相似文献
16.
Yun‐Fei Zhang Bin Wu Prof. Dr. Zhang‐Jie Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17808-17812
Ir‐catalyzed sp2 C?H amidation of aldehydes with various anilines as stoichiometric or catalytic directing groups was accomplished. A wide range of substrates were selectively amidated in good to excellent yields with broad functional group tolerance. The iridacycle complexes were isolated, characterized, and proved as key intermediates. Kinetic studies and Hammett plots provided detailed understandings of this amidation. According to the mechanism, the electron‐rich ArSO2N3 was proved effective for intermolecular sp3 C?H amidation. 相似文献
17.
Quan Gou Gang Liu Zi‐Ning Liu Prof. Dr. Jun Qin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15491-15495
PdII‐catalyzed intermolecular amination of unactivated C(sp3)?H bonds has been successfully developed for the first time. This method provides a new way to achieve the challenging intermolecular amination of unactivated C(sp3)?H bonds, producing a variety of unnatural β2‐amino carboxylic acid analogues. This C(sp3)?H amination protocol is demonstrated with a broad substrate scope, good functional‐group tolerance, and chemoselectivity. It is operated without use of phosphine ligand or external oxidant. 相似文献
18.
Site‐Selective δ‐C(sp3)−H Alkylation of Amino Acids and Peptides with Maleimides via a Six‐Membered Palladacycle
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Bei‐Bei Zhan Ya Li Jing‐Wen Xu Xing‐Liang Nie Dr. Jun Fan Liang Jin Prof. Dr. Bing‐Feng Shi 《Angewandte Chemie (International ed. in English)》2018,57(20):5858-5862
The site‐selective functionalization of unactivated C(sp3)?H bonds remains one of the greatest challenges in organic synthesis. Herein, we report on the site‐selective δ‐C(sp3)?H alkylation of amino acids and peptides with maleimides via a kinetically less favored six‐membered palladacycle in the presence of more accessible γ‐C(sp3)?H bonds. Experimental studies revealed that C?H bond cleavage occurs reversibly and preferentially at γ‐methyl over δ‐methyl C?H bonds while the subsequent alkylation proceeds exclusively at the six‐membered palladacycle that is generated by δ‐C?H activation. The selectivity can be explained by the Curtin–Hammett principle. The exceptional compatibility of this alkylation with various oligopeptides renders this procedure valuable for late‐stage peptide modifications. Notably, this process is also the first palladium(II)‐catalyzed Michael‐type alkylation reaction that proceeds through C(sp3)?H activation. 相似文献
19.
Zengbing Bai Chuangxu Cai Wangjian Sheng Yuxiang Ren Huan Wang 《Angewandte Chemie (International ed. in English)》2020,59(34):14686-14692
Transition‐metal‐catalyzed C?H activation has shown potential in the functionalization of peptides with expanded structural diversity. Herein, the development of late‐stage peptide macrocyclization methods by palladium‐catalyzed site‐selective C(sp2)?H olefination of tryptophan residues at the C2 and C4 positions is reported. This strategy utilizes the peptide backbone as endogenous directing groups and provides access to peptide macrocycles with unique Trp–alkene crosslinks. 相似文献
20.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(35):10675-10680
The silver‐catalyzed oxidative C(sp3)−H/P−H cross‐coupling of 1,3‐dicarbonyl compounds with H‐phosphonates, followed by a chemo‐ and regioselective C(sp3)−C(CO) bond‐cleavage step, provided heavily functionalized β‐ketophosphonates. This novel method based on a readily available reaction system exhibits wide scope, high functional‐group tolerance, and exclusive selectivity. 相似文献