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1.
Chao Wang Rupeng Qi Hongxiang Xue Yuxuan Shen Prof. Dr. Min Chang Yaqiong Chen Prof. Dr. Rui Wang Prof. Dr. Zhaoqing Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(19):7531-7536
Disclosed herein is the visible-light-promoted deaminative C(sp3)−H alkylation of glycine and peptides using Katritzky salts as electrophiles. Simple reaction conditions and excellent functional-group tolerance provide a general strategy for the efficient preparation of unnatural α-amino acids and precise modification of peptides with unnatural α-amino-acid residues. Mechanistic studies suggest that visible-light-promoted intermolecular charge transfer within a glycine–Katritzky salt electron donor-acceptor (EDA) complex induces a single-electron transfer process without the assistance of photocatalyst. 相似文献
2.
Xiang Yin Giuseppe Zuccarello Cristina García-Morales Prof. Dr. Antonio M. Echavarren 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(40):9485-9490
A novel synthesis of indanes and dihydronaphtalenes based on the intramolecular insertion into C(sp3)−H bonds of gold(I) carbenes generated by retro-Buchner reaction (decarbenation) has been developed. Deuterium-labeling and kinetic isotope effect experiments, DFT calculations, and generation of the proposed carbene intermediate from a well-characterized gold(I) carbenoid support the involvement of a three-center concerted mechanism for the C(sp3)−H functionalization process. 相似文献
3.
Gouranga Naskar Dr. Masilamani Jeganmohan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(39):e202200778
A palladium-catalyzed [3+2] annulation of substituted benzoic acids with maleimides leading to tricyclic heterocyclic molecules having a free carboxylic group in a high atom- and step-economical manner is described. The reaction proceeds via a dual C−H bond activation such as C(sp3)−H at the benzylic position and C(sp2)−H bond activation at the meta position of substituted aromatics. An external ligand (MPAA) is crucial for the success of present protocol. Further, the decarboxylation and esterification of the free carboxylic acid group of observed products were carried out. 相似文献
4.
Yichu Liu Yibing Wang Wenhao Dai Prof. Wei Huang Prof. Yingxia Li Prof. Hong Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3519-3522
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
5.
Palladium-catalyzed directing group assisted C−H bond activation has emerged as a powerful tool in synthetic organic chemistry. However, only recently, among various directing groups, widely available carboxylate moiety is recognized as a versatile candidate for the regioselective transformations. Notably, palladium-catalyzed carboxylate directed C(sp3)−H bond activation and diverse functionalization is highly challenging and has gained huge attention for its versatile applications. Mono- and bidentate ligands have proven to be useful for accelerating the C(sp3)−H bond activation step, which helps to control reactivity and selectivity (including enantioselectivity). In this Minireview, we discuss the recent progress made in palladium-catalyzed C(sp3)−H bond functionalization reactions for the construction of C−C and C−Heteroatom bonds with the direction of free carboxylic acid. 相似文献
6.
Arushi Garg Nils J. Gerwien Dr. Carlo Fasting Dr. Alex Charlton Dr. Matthew N. Hopkinson 《Angewandte Chemie (International ed. in English)》2023,62(25):e202302860
C−F Insertion reactions represent an attractive approach to prepare valuable fluorinated compounds. The high strength of C−F bonds and the low reactivity of the fluoride released upon C−F bond cleavage, however, mean that examples of such processes are extremely scarce in the literature. Here we report a reaction system that overcomes these challenges using hydrogen bond donors that both activate C−F bonds and allow for downstream reactions with fluoride. In the presence of hexafluoroisopropanol, benzyl and propargyl fluorides undergo efficient formal C−F bond insertion across α-fluorinated styrenes. This process, which does not require any additional fluorinating reagent, occurs under mild conditions and delivers products featuring the gem-difluoro motif, which is attracting increasing interest in medicinal chemistry. Moreover, readily available organic bromides can be engaged directly in a one-pot process that avoids the isolation of organic fluorides. 相似文献
7.
Àlex Díaz-Jiménez Roger Monreal-Corona Dr. Albert Poater Dr. María Álvarez Elena Borrego Prof. Dr. Pedro J. Pérez Dr. Ana Caballero Prof. Dr. Anna Roglans Dr. Anna Pla-Quintana 《Angewandte Chemie (International ed. in English)》2023,62(5):e202215163
The trapping of the elusive vinylogous position of a vinyl carbene with an aliphatic C(sp3)−H bond has been achieved for the first time during a silver-catalyzed carbene/alkyne metathesis (CAM) process. A Tpx-containing silver complex first promotes the generation of a donor-acceptor silver carbene which triggers CAM, generating a subsequent donor-donor vinyl silver carbene species, which then undergoes a selective vinylogous C(sp3)−H bond insertion, leading to the synthesis of a new family of benzoazepines. Density functional theory (DFT) calculations unveil the reaction mechanism, which allows proposing that the C−H bond insertion reaction takes place in a stepwise manner, with the hydrogen shift being the rate determining step. 相似文献
8.
Maximilian Stangier Alexej Scheremetjew Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201654
Electrochemical fluorinations of C(sp3)−H bonds with a nucleophilic fluoride source have been accomplished in a chemo- and site-selective fashion, avoiding the use of electrophilic F+ sources and stoichiometric oxidants. The introduced metal-free strategy exhibits high functional group tolerance, setting the stage for late-stage fluorinations of biorelevant motifs. The synthetic utility of the C(sp3)−H fluorination was reflected by subsequent one-pot arylation of the generated benzylic fluorides. 相似文献
9.
Dr. Matteo Virelli Wei Wang Dr. Rositha Kuniyil Jun Wu Prof. Dr. Giuseppe Zanoni Dr. Antonio Fernandez Jamie Scott Dr. Marc Vendrell Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(55):12712-12718
Arylated cyclobutanes were accessed by a versatile palladium-catalyzed secondary C(sp3)−H activation, exploiting chelation assistance by modular triazoles. The C−H arylation led to cyclobutane natural product derivatives in a highly regioselective fashion, setting the stage for the easy access to novel fluorogenic boron-dipyrrin (BODIPY)-labeled probes for live-cell imaging. 相似文献
10.
Dr. Ryohei Doi Akimasa Yabuta Prof. Dr. Yoshihiro Sato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(23):5884-5888
Palladium-catalyzed decarboxylative alkynylation of α-acyloxyketones triggered by C(sp3)−O bond cleavage is disclosed. The decarboxylation strategy featuring a neutral reaction condition enabled an unprecedent catalytic alkynylation of a ketone enolate. The reaction was applied to a variety of substrates, giving desired products in good yields. We successfully obtained X-ray crystallography of a new palladium–enolate intermediate that was synthesized by a reaction of [Pd(cod)(CH2TMS)2] with XPhos and α-acyloxyketone at room temperature, indicating facile C(sp3)−O bond disconnection. 相似文献
11.
Baptiste Neil Lamine Saadi Prof. Dr. Louis Fensterbank Dr. Clément Chauvier 《Angewandte Chemie (International ed. in English)》2023,62(31):e202306115
Benzylsilanes have found increasing applications in organic synthesis as bench-stable synthetic intermediates, yet are mostly produced by stoichiometric procedures. Catalytic alternatives based on the atom-economical silylation of benzylic C(sp3)−H bonds remain scarcely available as specialized directing groups and catalytic systems are needed to outcompete the kinetically-favored silylation of C(sp2)−H bonds. Herein, we describe the first general and catalytic-in-metal undirected silylation of benzylic C(sp3)−H bonds under ambient, transition metal-free conditions using stable tert-butyl-substituted silyldiazenes (tBu−N=N−SiR3) as silicon source. The high activity and selectivity of the catalytic system, exemplified by the preparation of various mono- or gem-bis benzyl(di)silanes, originates from the facile generation of organopotassium reagents, including tert-butylpotassium. 相似文献
12.
Ling Dai Ying-Ying Chen Prof. Li-Jun Xiao Prof. Qi-Lin Zhou 《Angewandte Chemie (International ed. in English)》2023,62(24):e202304427
Chiral benzylic amines are privileged motifs in pharmacologically active molecules. Intramolecular enantioselective radical C(sp3)−H functionalization by hydrogen-atom transfer has emerged as a straightforward, powerful tool for the synthesis of chiral amines, but methods for intermolecular enantioselective C(sp3)−H amination remain elusive. Herein, we report a cationic copper catalytic system for intermolecular enantioselective benzylic C(sp3)−H amination with peroxide as an oxidant. This mild, straightforward method can be used to transform an array of feedstock alkylarenes and amides into chiral amines with high enantioselectivities, and it has good functional group tolerance and broad substrate scope. More importantly, it can be used to synthesize bioactive molecules, including chiral drugs. Preliminary mechanistic studies indicate that the amination reaction involves benzylic radicals generated by hydrogen-atom transfer. 相似文献
13.
Mahesh Puthanveedu Vladislav Khamraev Lukas Brieger Prof. Dr. Carsten Strohmann Prof. Andrey P. Antonchick 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(30):8008-8012
A transition-metal-free direct electrolytic C−H amination involving an electrochemically generated nitrenium ion intermediate has been developed. The electrosynthesis takes place in the absence of any organoiodine catalysts and is enabled by an in situ generated electrolyte. A novel, efficient intramolecular and intermolecular C−H amination has been demonstrated using a simple reaction setup. 相似文献
14.
Dr. Yu-Feng Zhang Jia-Huan Wang Ning-Yuan Yang Zheng Chen Li-Lei Wang Dr. Qiang-Shuai Gu Dr. Zhong-Liang Li Dr. Xin-Yuan Liu 《Angewandte Chemie (International ed. in English)》2023,62(27):e202302983
Transition-metal catalyzed enantioconvergent cross-coupling of tertiary alkyl halides with ammonia offers a rapid avenue to chiral unnatural α,α-disubstituted amino acids. However, the construction of chiral C−N bonds between tertiary-carbon electrophiles and nitrogen nucleophiles presented a great challenge owing to steric congestion. We report a copper-catalyzed enantioconvergent radical C−N cross-coupling of alkyl halides with sulfoximines (as ammonia surrogates) under mild conditions by employing a chiral anionic N,N,N-ligand with a long spreading side arm. An array of α,α-disubstituted amino acid derivatives were obtained with good efficiency and enantioselectivity. The synthetic utility of the strategy has been showcased by the elaboration of the coupling products into different chiral α-fully substituted amine building blocks. 相似文献
15.
Anton Kudashev Prof. Dr. Olivier Baudoin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(70):17688-17694
A ligand-controlled site-selective C(sp3)−H arylation of heteroaromatic ketones has been developed using Pd catalysis. The reaction occurred selectively at the α- or β-position of the ketone side-chain. The switch from α- to β-arylation was realized by addition of a pyridone ligand. The α-arylation process showed broad scope and high site- and chemoselectivity, whereas the β-arylation was more limited. Mechanistic investigations suggested that α-arylation occurs through C−H activation/oxidative addition/reductive elimination whereas β-arylation involves desaturation and aryl insertion. 相似文献
16.
Dr. Yingle Mao Weijie Zhang Dr. Zunyun Fu Yanqiong Liu Lin Chen Xin Lian Dan Zhuo Prof. Jiewei Wu Prof. Mingyue Zheng Prof. Cangsong Liao 《Angewandte Chemie (International ed. in English)》2023,62(33):e202305250
C(sp3)−H oxyfunctionalization, the insertion of an O-atom into C(sp3)−H bonds, streamlines the synthesis of complex molecules from easily accessible precursors and represents one of the most challenging tasks in organic chemistry with regard to site and stereoselectivity. Biocatalytic C(sp3)−H oxyfunctionalization has the potential to overcome limitations inherent to small-molecule-mediated approaches by delivering catalyst-controlled selectivity. Through enzyme repurposing and activity profiling of natural variants, we have developed a subfamily of α-ketoglutarate-dependent iron dioxygenases that catalyze the site- and stereodivergent oxyfunctionalization of secondary and tertiary C(sp3)−H bonds, providing concise synthetic routes towards four types of 92 α- and β-hydroxy acids with high efficiency and selectivity. This method provides a biocatalytic approach for the production of valuable but synthetically challenging chiral hydroxy acid building blocks. 相似文献
17.
Daisuke Yamauchi Dr. Takahiro Nishimura Prof. Dr. Hideki Yorimitsu 《Angewandte Chemie (International ed. in English)》2017,56(25):7200-7204
Direct alkylation of a methyl group, on di- and trisubstituted ureas, with terminal alkenes by C(sp3)−H bond activation proceeded in the presence of a hydroxoiridium/bisphosphine catalyst to give high yields of the corresponding addition products. The hydroxoiridium/bisphosphine complex generates an amidoiridium intermediate by reaction with ureas having an N−H bond. 相似文献
18.
David Dailler Ronan Rocaboy Prof. Dr. Olivier Baudoin 《Angewandte Chemie (International ed. in English)》2017,56(25):7218-7222
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
19.
Dimitris I. Ioannou Prof. Dr. Luca Capaldo Jiri Sanramat Prof. Dr. Joost N. H. Reek Prof. Dr. Timothy Noël 《Angewandte Chemie (International ed. in English)》2023,62(52):e202315881
Electrophotocatalytic transformations are garnering attention in organic synthesis, particularly for accessing reactive intermediates under mild conditions. Moving these methodologies to continuous-flow systems, or flow ElectroPhotoCatalysis (f-EPC), showcases potential for scalable processes due to enhanced irradiation, increased electrode surface, and improved mixing of the reaction mixture. Traditional methods sequentially link photochemical and electrochemical reactions, using flow reactors connected in series, yet struggle to accommodate reactive transient species. In this study, we introduce a new flow reactor concept for electrophotocatalysis (EPC) that simultaneously utilizes photons and electrons. The reactor is designed with a transparent electrode and employs cost-effective materials. We used this technology to develop an efficient process for electrophotocatalytic heteroarylation of C(sp3)−H bonds. Importantly, the same setup can also facilitate purely electrochemical and photochemical transformations. This reactor represents a significant advancement in electrophotocatalysis, providing a framework for its application in flow for complex synthetic transformations. 相似文献
20.
Tian Xie Dr. Lili Chen Dr. Zhenlu Shen Dr. Senmiao Xu 《Angewandte Chemie (International ed. in English)》2023,62(14):e202300199
Reported here is an efficient and simple ether-directed iridium-catalyzed enantioselective C(sp3)−H borylation of cyclopropanes. Various functional groups were well-tolerated, affording a vast array of chiral cyclopropanes with high enantioselectivities. We also demonstrated that the turnover numbers of the current reaction could be up to 335. 相似文献