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1.
Dr. Rishikesh Narayan Dr. Kiran Matcha Dr. Andrey P. Antonchick 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(42):14678-14693
The formation of C?C bonds embodies the core of organic chemistry because of its fundamental application in generation of molecular diversity and complexity. C?C bond‐forming reactions are well‐known challenges. To achieve this goal through direct functionalization of C?H bonds in both of the coupling partners represents the state‐of‐the‐art in organic synthesis. Oxidative C?C bond formation obviates the need for prefunctionalization of both substrates. This Minireview is dedicated to the field of C?C bond‐forming reactions through direct C?H bond functionalization under completely metal‐free oxidative conditions. Selected important developments in this area have been summarized with representative examples and discussions on their reaction mechanisms. 相似文献
2.
Dr. Amélie Pialat Julien Bergès Axel Sabourin Robin Vinck Dr. Benoît Liégault Dr. Marc Taillefer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10014-10018
The direct, nucleophilic imidation of acetanilide derivatives has been performed under mild, iodine(III)‐mediated or ‐catalyzed conditions, employing lithium triflimide as the nitrogen source. The reaction exhibits exclusive regioselectivity for the para position and shows a good tolerance for varied functional groups at both the ortho or meta positions. Preliminary mechanistic data suggest that the LiNTf2 reagent plays a key role in the reactivity. 相似文献
3.
Palladium‐Catalyzed Construction of Heteroatom‐Containing π‐Conjugated Systems by Intramolecular Oxidative CH/CH Coupling Reaction 下载免费PDF全文
Kenta Saito Dr. Prasanna Kumara Chikkade Prof. Dr. Motomu Kanai Prof. Dr. Yoichiro Kuninobu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(23):8365-8368
Synthesis of heteroatom‐containing ladder‐type π‐conjugated molecules was successfully achieved via a palladium‐catalyzed intramolecular oxidative C?H/C?H cross‐coupling reaction. This reaction provides a variety of π‐conjugated molecules bearing heteroatoms, such as nitrogen, oxygen, phosphorus, and sulfur atoms, and a carbonyl group. The π‐conjugated molecules were synthesized efficiently, even in gram scale, and larger π‐conjugated molecules were also obtained by a double C?H/C?H cross‐coupling reaction and successive oxidative cycloaromatization. 相似文献
4.
The catalytic cross‐dehydrogenative coupling (CDC) reaction has received intense attention in recent years. The attractive feature of this coupling process is the formation of a C? C bond from two C? H moieties under oxidative conditions. In this Focus Review, recent advances in the palladium‐catalyzed CDC reactions of C(sp2)? H bond are summarized, with a focus on the period from 2011 to early 2013. 相似文献
5.
Xiaoge Yang Zhuqing Liu Prof. Chenglin Sun Prof. Dr. Jiping Chen Prof. Dr. Zhengkun Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(40):14085-14094
Efficient palladium‐catalyzed cross‐coupling reactions of the internal olefins α‐cyanoketene dithioacetals with a variety of olefins were achieved in dioxane/HOAc/DMSO (9:3:1 v/v/v) under air atmosphere or by means of AgOAc as the terminal oxidant. Electron‐deficient terminal olefins reacted to form the linear diene derivatives with air as the oxidant. Styrenes underwent the cross‐coupling to give both the linear and branched dienes when using AgOAc as the oxidant. Unactivated cyclic and linear internal olefin substrates both reacted in the presence of a catalytic amount of benzoquinone in air to produce skipped dienes. The typical products were structurally confirmed by X‐ray crystallography. 相似文献
6.
Copper/Silver‐Mediated Direct ortho‐Ethynylation of Unactivated (Hetero)aryl CH Bonds with Terminal Alkyne 下载免费PDF全文
Yue‐Jin Liu Yan‐Hua Liu Xue‐Song Yin Wen‐Jia Gu Prof. Dr. Bing‐Feng Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):205-209
A copper/silver‐mediated oxidative ortho‐ethynylation of unactivated aryl C?H bonds with terminal alkyne has been developed. The reaction uses the removable PIP directing group and features broad substrate scope, high functional‐group tolerance, and compatibility with a wide range of heterocycles, providing an efficient synthesis of aryl alkynes. This procedure highlights the potential of copper catalysts to promote unique, synthetically enabling C?H functionalization reactions that lie outside of the current scope of precious metal catalysis. 相似文献
7.
Fen Wang Xinzhang Yu Zisong Qi Prof. Dr. Xingwei Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(2):511-516
Rhodium‐catalyzed sulfonylation, thioetherification, thiocyanation, and other heterofunctionalizations of arenes bearing a heterocyclic directing group have been realized. The reaction proceeds by initial RhIII‐catalyzed C?H hyperiodination of arene at room temperature followed by uncatalyzed nucleophilic functionalization. A diaryliodonium salt is isolated as an intermediate, which represents umpolung of the arene substrate, in contrast to previous studies that suggested umpolung of the coupling partner. 相似文献
8.
Selective CH Functionalization of Methane,Ethane, and Propane by a Perfluoroarene Iodine(III) Complex 下载免费PDF全文
Dr. Michael M. Konnick Dr. Brian G. Hashiguchi Dr. Deepa Devarajan Nicholas C. Boaz Prof. T. Brent Gunnoe Prof. John T. Groves Niles Gunsalus Prof. Daniel H. Ess Prof. Roy A. Periana 《Angewandte Chemie (International ed. in English)》2014,53(39):10490-10494
Direct partial oxidation of methane, ethane, and propane to their respective trifluoroacetate esters is achieved by a homogeneous hypervalent iodine(III) complex in non‐superacidic (trifluoroacetic acid) solvent. The reaction is highly selective for ester formation (>99 %). In the case of ethane, greater than 0.5 M EtTFA can be achieved. Preliminary kinetic analysis and density functional calculations support a nonradical electrophilic CH activation and iodine alkyl functionalization mechanism. 相似文献
9.
Kinetic Studies on the Palladium(II)‐Catalyzed Oxidative Cross‐Coupling of Thiophenes with Arylboron Compounds and Their Mechanistic Implications 下载免费PDF全文
Dr. Ingo Schnapperelle Dr. Stefan Breitenlechner Prof. Dr. Thorsten Bach 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(50):18407-18416
Reaction orders for the key components in the palladium(II)‐catalyzed oxidative cross‐coupling between phenylboronic acid and ethyl thiophen‐3‐yl acetate were obtained by the method of initial rates. It turned out that the reaction rate not only depended on the concentration of palladium trifluoroacetate (reaction order: 0.97) and phenylboronic acid (reaction order: 1.26), but also on the concentration of the thiophene (reaction order: 0.55) and silver oxide (reaction order: ?1.27). NMR spectroscopy titration studies established the existence of 1:1 complexes between the silver salt and both phenylboronic acid and ethyl thiophen‐3‐yl acetate. A low inverse kinetic isotope effect (kH/kD=0.93) was determined upon employing the 4‐deuterated isotopomer of ethyl thiophen‐3‐yl acetate and monitoring its reaction to the 4‐phenyl‐substituted product. A Hammett analysis performed with para‐substituted 2‐phenylthiophenes gave a negative ρ value for oxidative cross‐coupling with phenylboronic acid. Based on the kinetic data and additional evidence, a mechanism is suggested that invokes transfer of the phenyl group from phenylboronic acid to a 1:1 complex of palladium trifluoroacetate and thiophene as the rate‐determining step. Proposals for the structure of relevant intermediates are made and discussed. 相似文献
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11.
Shuo Guo Xiaofei Zhang Prof. Dr. Pingping Tang 《Angewandte Chemie (International ed. in English)》2015,54(13):4065-4069
The first example of a practical and direct trifluoromethylthiolation reaction of unactivated aliphatic C? H bonds employs a silver‐based reagent. The reaction is operationally simple, scalable, and proceeds under aqueous conditions in air. Furthermore, its broad scope and good functional‐group compatibility were demonstrated by applying this method to the selective trifluoromethylthiolation of natural products and natural‐product derivatives. 相似文献
12.
Christopher J. Teskey Andrew Y. W. Lui Prof. Michael F. Greaney 《Angewandte Chemie (International ed. in English)》2015,54(40):11677-11680
The first example of a transition‐metal‐catalyzed, meta‐selective C? H bromination procedure is reported. In the presence of catalytic [{Ru(p‐cymene)Cl2}2], tetrabutylammonium tribromide can be used to functionalize the meta C? H bond of 2‐phenylpyridine derivatives, thus affording difficult to access products which are highly predisposed to further derivatization. We demonstrate this utility with one‐pot bromination/arylation and bromination/alkenylation procedures to deliver meta‐arylated and meta‐alkenylated products, respectively, in a single step. 相似文献
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Transition Metal‐Catalyzed Carbonylative CH Bond Functionalization of Arenes and C(sp3)H Bond of Alkanes 下载免费PDF全文
Sandip T. Gadge Prashant Gautam Bhalchandra M. Bhanage 《Chemical record (New York, N.Y.)》2016,16(2):835-856
In this article, we present the progress made in the area of carbonylative C? H functionalization, with special emphasis on arenes and alkanes. The importance of directing group assistance and C? H functionalization using CO surrogates is also included. The budding development in the area of transition metal‐catalyzed C(sp3)? H activation makes us feel it necessary to file a summary on the past, as well as current, contributions and a prospective outlook on the transition metal‐catalyzed carbonylative transformation of C? H bonds, which is the focus of this review. 相似文献
15.
Palladium‐Catalyzed/Norbornene‐Mediated CH Activation/ N‐Tosylhydrazone Insertion Reaction: A Route to Highly Functionalized Vinylarenes 下载免费PDF全文
Dr. Ping‐Xin Zhou Lan Zheng Jun‐Wei Ma Yu‐Ying Ye Xue‐Yuan Liu Prof. Dr. Peng‐Fei Xu Prof. Dr. Yong‐Min Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(22):6745-6751
A straightforward method for the synthesis of highly functionalized vinylarenes through palladium‐catalyzed, norbornene‐mediated C?H activation/carbene migratory insertion is described. Extension to a one‐pot procedure is also developed. Furthermore, this method can also be used to generate polysubstituted bicyclic molecules. The reaction proceeds under mild conditions to give the products in satisfactory yields using readily available starting materials. This is a Catellani–Lautens reaction that incorporates different types of coupling partners. Additionally, this reaction is the first to demonstrate the possibility of combining Pd‐catalyzed insertion of diazo compounds and Pd‐catalyzed C?H activation. 相似文献
16.
Dr. Lu Li Xiaoyue Mu Wenbo Liu Xianghua Kong Shizhao Fan Prof. Dr. Zetian Mi Prof. Dr. Chao‐Jun Li 《Angewandte Chemie (International ed. in English)》2014,53(51):14106-14109
The thermal catalytic activity of GaN in non‐oxidative alkane dehydroaromatization has been discovered for the first time. The origin of the catalytic activity was studied experimentally and theoretically. Commercially available GaN powders with a wurtzite crystal structure showed superior stability and reactivity for converting light alkanes, including methane, propane, n‐butane, n‐hexane and cyclohexane into benzene at an elevated temperature with high selectivity. The catalyst is highly robust and can be used repeatedly without noticeable deactivation. 相似文献
17.
Dr. Dmitry Katayev Kai F. Pfister Timo Wendling Prof. Dr. Lukas J. Gooßen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9902-9905
Various (hetero)arenecarboxylic acids were converted to the corresponding Daugulis amides and nitrated selectively in the ortho‐position in the presence of [CuNO3(PPh3)2] and AgNO2 at 50 °C. A microwave‐assisted saponification allows regenerating the carboxylate group within minutes, which may then be removed tracelessly by protodecarboxylation, or substituted by aryl‐ or alkoxy‐groups via decarboxylative cross‐coupling. 相似文献
18.
Synthesis of Indazoles and Azaindazoles by Intramolecular Aerobic Oxidative CN Coupling under Transition‐Metal‐Free Conditions 下载免费PDF全文
Jiantao Hu Huacheng Xu Pengju Nie Xiaobo Xie Prof. Dr. Zongxiu Nie Prof. Dr. Yu Rao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(14):3932-3938
A transition‐metal‐free oxidative C?N coupling method has been developed for the synthesis of 1H‐azaindazoles and 1H‐indazoles from easily accessible hydrazones. The procedure uses TEMPO, a basic additive, and dioxygen gas as the terminal oxidant. This reaction demonstrates better reactivity, functional group tolerance, and broader scope than comparable metal catalyzed reactions. 相似文献
19.
Corrigendum: Diastereo‐ and Enantioselective Intramolecular C(sp3)H Arylation for the Synthesis of Fused Cyclopentanes 下载免费PDF全文
Dr. Nicolas Martin Cathleen Pierre Dr. Michaël Davi Dr. Rodolphe Jazzar Prof. Dr. Olivier Baudoin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(39):12341-12341