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Jompol Thongpaen Romane Manguin Olivier Basl 《Angewandte Chemie (International ed. in English)》2020,59(26):10242-10251
The asymmetric functionalization of C?H bond is a particularly valuable approach for the production of enantioenriched chiral organic compounds. Chiral N‐heterocyclic carbene (NHC) ligands have become ubiquitous in enantioselective transition‐metal catalysis. Conversely, the use of chiral NHC ligands in metal‐catalyzed asymmetric C?H bond functionalization is still at an early stage. This minireview highlights all the developments and the new advances in this rapidly evolving research area. 相似文献
3.
Ruthenium(II)‐Catalyzed Traceless C−H Functionalization Using an N−N Bond as an Internal Oxidant
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Dr. Shuguang Zhou Jinhu Wang Pei Chen Kehao Chen Prof. Dr. Jin Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14508-14512
A previously elusive RuII‐catalyzed N?N bond‐based traceless C?H functionalization strategy is reported. An N‐amino (i.e., hydrazine) group is used for the directed C?H functionalization with either an alkyne or an alkene, affording an indole derivative or olefination product. The synthesis features a broad substrate scope, superior atom and step economy, as well as mild reaction conditions. 相似文献
4.
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
5.
A General Approach to Site‐Specific,Intramolecular C−H Functionalization Using Dithiocarbamates
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Christina G. Na Prof. Erik J. Alexanian 《Angewandte Chemie (International ed. in English)》2018,57(40):13106-13109
Intramolecular hydrogen atom transfer is an established approach for the site‐specific functionalization of unactivated, aliphatic C?H bonds. Transformations using this strategy typically require unstable intermediates formed using strong oxidants and have mainly targeted C?H halogenations or intramolecular aminations. Herein, we report a site‐specific C?H functionalization that significantly increases the synthetic scope and convergency of reactions proceeding via intramolecular hydrogen atom transfer. Stable, isolable N‐dithiocarbamates are used as precursors to amidyl radicals formed via either light or radical initiation to efficiently deliver highly versatile alkyl dithiocarbamates across a wide range of complex structures. 相似文献
6.
Xiao‐Li Lai Xiao‐Min Shu Jinshuai Song Hai‐Chao Xu 《Angewandte Chemie (International ed. in English)》2020,59(26):10626-10632
Decarboxylative C?H functionalization reactions are highly attractive methods for forging carbon–carbon bonds considering their inherent step‐ and atom‐economical features and the pervasiveness of carboxylic acids and C?H bonds. An ideal approach to achieve these dehydrogenative transformations is through hydrogen evolution without using any chemical oxidants. However, effective couplings by decarboxylative carbon–carbon bond formation with proton reduction remain an unsolved challenge. Herein, we report an electrophotocatalytic approach that merges organic electrochemistry with photocatalysis to achieve the efficient direct decarboxylative C?H alkylation and carbamoylation of heteroaromatic compounds through hydrogen evolution. This electrophotocatalytic method, which combines the high efficiency and selectivity of photocatalysis in promoting decarboxylation with the superiority of electrochemistry in effecting proton reduction, enables the efficient coupling of a wide range of heteroaromatic bases with a variety of carboxylic acids and oxamic acids. Advantageously, this method is scalable to decagram amounts, and applicable to the late‐stage functionalization of drug molecules. 相似文献
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Daniel Bafaluy Jos María Muoz‐Molina Ignacio Funes‐Ardoiz Sebastian Herold Adiran J. deAguirre Hongwei Zhang Feliu Maseras Toms R. Belderrain Pedro J. Prez Kilian Muiz 《Angewandte Chemie (International ed. in English)》2019,58(26):8912-8916
The dual function of the N?F bond as an effective oxidant and subsequent nitrogen source in intramolecular aliphatic C?H functionalization reactions is explored. Copper catalysis is demonstrated to exercise full regio‐ and chemoselectivity control, which opens new synthetic avenues to nitrogenated heterocycles with predictable ring sizes. For the first time, a uniform catalysis manifold has been identified for the construction of both pyrrolidine and piperidine cores. The individual steps of this new copper oxidation catalysis were elucidated by control experiments and computational studies, clarifying the singularity of the N?F function and characterizing the catalytic cycle to be based on a copper(I/II) manifold. 相似文献
8.
A novel radical‐based approach for the iron‐catalyzed selective cleavage of acetal‐derived alkylsilyl peroxides, followed by the formation of a carbon–carbon bond is reported. The reaction proceeds under mild reaction conditions and exhibits a broad substrate scope with respect to the acetal moiety and the carbon electrophile. Mechanistic studies suggest that the present reaction proceeds through a free‐radical process involving carbon radicals generated by the homolytic cleavage of a carbon–carbon bond within the acetal moiety. A synthetic application of this method to sugar‐derived alkylsilyl peroxides is also described. 相似文献
9.
Dr. Jun Xu Dr. Chao Shen Dr. Xiaolei Zhu Prof. Pengfei Zhang Dr. Manjaly J. Ajitha Prof. Kuo‐Wei Huang Dr. Zhongfu An Prof. Xiaogang Liu 《化学:亚洲杂志》2016,11(6):882-892
Achieving site selectivity in carbon–hydrogen (C?H) functionalization reactions is a formidable challenge in organic chemistry. Herein, we report a novel approach to activating remote C?H bonds at the C5 position of 8‐aminoquinoline through copper‐catalyzed sulfonylation under mild conditions. Our strategy shows high conversion efficiency, a broad substrate scope, and good toleration with different functional groups. Furthermore, our mechanistic investigations suggest that a single‐electron‐transfer process plays a vital role in generating sulfonyl radicals and subsequently initiating C?S cross‐coupling. Importantly, our copper‐catalyzed remote functionalization protocol can be expanded for the construction of a variety of chemical bonds, including C?O, C?Br, C?N, C?C, and C?I. These findings provide a fundamental insight into the activation of remote C?H bonds, while offering new possibilities for rational design of drug molecules and optoelectronic materials requiring specific modification of functional groups. 相似文献
10.
Ethan A. Wappes Stacy C. Fosu Trevor C. Chopko Prof. Dr. David A. Nagib 《Angewandte Chemie (International ed. in English)》2016,55(34):9974-9978
The Cδ?H amination of unactivated, secondary C?H bonds to form a broad range of functionalized pyrrolidines has been developed by a triiodide (I3?)‐mediated strategy. By in situ 1) oxidation of sodium iodide and 2) sequestration of the transiently generated iodine (I2) as I3?, this approach precludes undesired I2‐mediated decomposition which can otherwise limit synthetic utility to only weak C(sp3)?H bonds. The mechanism of this triiodide‐mediated cyclization of unbiased, secondary C(sp3)?H bonds, by either thermal or photolytic initiation, is supported by NMR and UV/Vis data, as well as intercepted intermediates. 相似文献
11.
Olivier Baudoin 《Angewandte Chemie (International ed. in English)》2020,59(41):17798-17809
In the past decade, multiple catalytic C?H bond functionalization has been successfully applied in natural product synthesis as a strategy to reduce the number of steps, increase overall yield and employ more easily available starting materials. This minireview presents selected examples making use of multiple C?H bond functionalization in conceptually different ways. First, linear syntheses are discussed, wherein multiple C?H functionalization is employed either from simple (hetero)cyclic cores, at a late stage, or to build polycyclic systems. Second, the use of multiple C?H functionalization as a strategic tool in convergent synthesis to access and couple complex fragments is discussed. Information on the scalability of the employed methods is provided when available. The presented cases indicate that multiple C?H functionalization strategies should play a great role to shape the future synthesis of functional complex molecules with improved sustainability. 相似文献
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Eosin Y as a Direct Hydrogen‐Atom Transfer Photocatalyst for the Functionalization of C−H Bonds
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Xuan‐Zi Fan Dr. Jia‐Wei Rong Hao‐Lin Wu Quan Zhou Dr. Hong‐Ping Deng Jin Da Tan Cheng‐Wen Xue Dr. Li‐Zhu Wu Dr. Hai‐Rong Tao Dr. Jie Wu 《Angewandte Chemie (International ed. in English)》2018,57(28):8514-8518
Eosin Y, a well‐known economical alternative to metal catalysts in visible‐light‐driven single‐electron transfer‐based organic transformations, can behave as an effective direct hydrogen‐atom transfer catalyst for C?H activation. Using the alkylation of C?H bonds with electron‐deficient alkenes as a model study revealed an extremely broad substrate scope, enabling easy access to a variety of important synthons. This eosin Y‐based photocatalytic hydrogen‐atom transfer strategy is promising for diverse functionalization of a wide range of native C?H bonds in a green and sustainable manner. 相似文献
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Bifunctional RuII‐Complex‐Catalysed Tandem C−C Bond Formation: Efficient and Atom Economical Strategy for the Utilisation of Alcohols as Alkylating Agents
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Bivas Chandra Roy Kaushik Chakrabarti Sujan Shee Subhadeep Paul Dr. Sabuj Kundu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):18147-18155
Catalytic activities of a series of functional bipyridine‐based RuII complexes in β‐alkylation of secondary alcohols using primary alcohols were investigated. Bifunctional RuII complex ( 3 a ) bearing 6,6’‐dihydroxy‐2,2’‐bipyridine (6DHBP) ligand exhibited the highest catalytic activity for this reaction. Using significantly lower catalyst loading (0.1 mol %) dehydrogenative carbon?carbon bond formation between numerous aromatic, aliphatic and heteroatom substituted alcohols were achieved with high selectivity. Notably, for the synthesis of β‐alkylated secondary alcohols this protocol is a rare one‐pot strategy using a metal–ligand cooperative RuII system. Remarkably, complex 3 a demonstrated the highest reactivity compared to all the reported transition metal complexes in this reaction. 相似文献
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Takeshi Fujita Kohei Fuchibe Junji Ichikawa 《Angewandte Chemie (International ed. in English)》2019,58(2):390-402
The activation of carbon–fluorine (C?F) bonds is an important topic in synthetic organic chemistry. Metal‐mediated and ‐catalyzed elimination of β‐ or α‐fluorine proceeds under milder conditions than oxidative addition to C?F bonds. The β‐ or α‐fluorine elimination is initiated from organometallic intermediates having fluorine substituents on carbon atoms β or α to metal centers, respectively. Transformations through these elimination processes (C?F bond cleavage), which are typically preceded by carbon–carbon (or carbon–heteroatom) bond formation, have been increasingly developed in the past five years as C?F bond activation methods. In this Minireview, we summarize the applications of transition‐metal‐mediated and ‐catalyzed fluorine elimination to synthetic organic chemistry from a historical perspective with early studies and from a systematic perspective with recent studies. 相似文献
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Regioselective Hydrohydroxyalkylation of Styrene with Primary Alcohols or Aldehydes via Ruthenium‐Catalyzed C−C Bond Forming Transfer Hydrogenation
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Hongde Xiao Gang Wang Prof. Michael J. Krische 《Angewandte Chemie (International ed. in English)》2016,55(52):16119-16122
Transfer hydrogenative coupling of styrene with primary alcohols using the precatalyst HClRu(CO)(PCy3)2 modified by AgOTf or HBF4 delivers branched or linear adducts from benzylic or aliphatic alcohols, respectively. Related 2‐propanol mediated reductive couplings also are described. 相似文献
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Dr. Martin Pichette Drapeau Prof. Dr. Lukas J. Gooßen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(52):18654-18677
The selective transformation of C?H bonds is one of the most desirable approaches to creating complexity from simple building blocks. Several directing groups are efficient in controlling the regioselectivity of catalytic C?H bond functionalizations. Among them, carboxylic acids are particularly advantageous, since they are widely available in great structural diversity and at low cost. The carboxylate directing groups can be tracelessly cleaved or may serve as the anchor point for further functionalization through decarboxylative couplings. This Minireview summarizes the substantial progress made in the last few years in the development of reactions in which carboxylate groups direct C?H bond functionalizations with formation of C?C, C?O, C?N, or C?halogen bonds at specific positions. It is divided into sections on C?C, C?O, C?N, and C?halogen bond formation, each of which is subdivided by reactions and product classes. Particular emphasis is placed on methods that enable multiple derivatizations by combining carboxylate‐directed C?H functionalization with decarboxylative couplings. 相似文献
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Dr. Jens Atzrodt Dr. Volker Derdau Prof. Dr. William J. Kerr Dr. Marc Reid 《Angewandte Chemie (International ed. in English)》2018,57(12):3022-3047
The various applications of hydrogen isotopes (deuterium, D, and tritium, T) in the physical and life sciences demand a range of methods for their installation in an array of molecular architectures. In this Review, we describe recent advances in synthetic C?H functionalisation for hydrogen isotope exchange. 相似文献
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Tertiary‐Alcohol‐Directed Functionalization of Remote C(sp3)−H Bonds by Sequential Hydrogen Atom and Heteroaryl Migrations
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Xinxin Wu Mingyang Wang Leitao Huan Dongping Wang Jinwei Wang Prof. Dr. Chen Zhu 《Angewandte Chemie (International ed. in English)》2018,57(6):1640-1644
Reported for the first time is a tertiary‐alcohol‐guided heteroarylation of remote C(sp3)?H bonds. The mild and direct generation of alkoxyl radicals from alcohols is enabled by visible‐light photocatalysis. A remote hydrogen atom and heteroaryl migration sequence are involved in the reaction. Many sensitive groups remain intact in the reaction, thus illustrating wide functional‐group compatibility. This protocol provides a practical strategy for the late‐stage modification of alkyl ketones. 相似文献
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《化学:亚洲杂志》2017,12(2):239-247
Five bis(quinolylmethyl)‐(1H ‐indolylmethyl)amine (BQIA) compounds, that is, {(quinol‐8‐yl‐CH2)2NCH2(3‐Br‐1H ‐indol‐2‐yl)} ( L1H ) and {[(8‐R3‐quinol‐2‐yl)CH2]2NCH(R2)[3‐R1‐1H ‐indol‐2‐yl]} ( L2–5H ) ( L2H : R1=Br, R2=H, R3=H; L3H : R1=Br, R2=H, R3=i Pr; L4H : R1=H, R2=CH3, R3=i Pr; L5H : R1=H, R2=n Bu, R3=i Pr) were synthesized and used to prepare calcium complexes. The reactions of L1–5H with silylamido calcium precursors (Ca[N(SiMe2R)2]2(THF)2, R=Me or H) at room temperature gave heteroleptic products ( L1, 2 )CaN(SiMe3)2 ( 1 , 2 ), ( L3, 4 )CaN(SiHMe2)2 ( 3 a , 4 a ) and homoleptic complexes ( L3, 5 )2Ca ( D3 , D5 ). NMR and X‐ray analyses proved that these calcium complexes were stabilized through Ca⋅⋅⋅C−Si, Ca⋅⋅⋅H−Si or Ca⋅⋅⋅H−C agostic interactions. Unexpectedly, calcium complexes (( L3–5 )CaN(SiMe3)2) bearing more sterically encumbered ligands of the same type were extremely unstable and underwent C−N bond cleavage processes as a consequence of intramolecular C−H bond activation, leading to the exclusive formation of (E )‐1,2‐bis(8‐isopropylquinol‐2‐yl)ethane. 相似文献
20.
Site‐Selective Remote Radical C−H Functionalization of Unactivated C−H Bonds in Amides Using Sulfone Reagents
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Dr. Yong Xia Lin Wang Prof. Dr. Armido Studer 《Angewandte Chemie (International ed. in English)》2018,57(39):12940-12944
A general and practical strategy for remote site‐selective functionalization of unactivated aliphatic C?H bonds in various amides by radical chemistry is introduced. C?H bond functionalization is achieved by using the readily installed N‐allylsulfonyl moiety as an N‐radical precursor. The in situ generated N‐radical engages in intramolecular 1,5‐hydrogen atom transfer to generate a translocated C radical which is subsequently trapped with various sulfone reagents to afford the corresponding C?H functionalized amides. The generality of the approach is documented by the successful remote C?N3, C?Cl, C?Br, C?SCF3, C?SPh, and C?C bond formation. Unactivated tertiary and secondary C?H bonds, as well as activated primary C?H bonds, can be readily functionalized by this method. 相似文献