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1.
Dr. Shubhankar Kumar Bose Andrea Deißenberger Antonius Eichhorn Prof. Dr. Patrick G. Steel Prof. Dr. Zhenyang Lin Prof. Dr. Todd B. Marder 《Angewandte Chemie (International ed. in English)》2015,54(40):11843-11847
A zinc‐catalyzed combined C? X and C? H borylation of aryl halides using B2pin2 (pin=OCMe2CMe2O) to produce the corresponding 1,2‐diborylarenes under mild conditions was developed. Catalytic C? H bond activation occurs ortho to the halide groups if such a site is available or meta to the halide if the ortho position is already substituted. This method thus represents a novel use of a group XII catalyst for C? H borylation. This transformation does not proceed via a free aryne intermediate, but a radical process seems to be involved. 相似文献
2.
Saqib A. Iqbal Jessica Cid Richard J. Procter Marina Uzelac Kang Yuan Michael J. Ingleson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(43):15525-15529
Indoles are privileged heterocycles found in many biologically active pharmaceuticals and natural products. However, the selective functionalization of the benzenoid moiety in indoles in preference to the more reactive pyrrolic unit is a significant challenge. Herein we report that N‐acyl directing groups enable the C7‐selective C?H borylation of indoles using just BBr3. This transformation shows some functional‐group tolerance and notably proceeds with C6 substituted indoles. The directing group can be readily removed in situ and the products isolated as the pinacol boronate esters. Acyl‐directed electrophilic borylation can be extended to carbazoles and anilines with excellent ortho selectivity. 4‐amino‐indoles are amenable to this process, with acyl group installation and directed electrophilic C?H borylation enabling selective formation of C5‐BPin‐indoles. 相似文献
3.
Ruijie Mi Guangfan Zheng Zisong Qi Xingwei Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(49):17830-17834
C?H bond activation is mostly limited to ortho selectivity. Activation of both ortho and meta C?H bonds constitutes a particularly important strategy for annulation, but has rarely been studied in enantioselective systems. Reported herein is rhodium(III)‐catalyzed asymmetric [3+2] transannulation of arenes with 7‐azabenzonorbornadienes. Two distinct classes of arenes have been identified as substrates, and the coupling proceeded with high enantioselectivity and excellent diastereoselectivity through sequential activation of ortho and meta C?H bonds. 相似文献
4.
Jian Wen Dingyi Wang Jiasheng Qian Di Wang Chendan Zhu Yue Zhao Zhuangzhi Shi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(7):2100-2104
Transition‐metal‐mediated metalation of an aromatic C?H bond that is adjacent to a tertiary phosphine group in arylphosphines via a four‐membered chelate ring was first discovered in 1968. Herein, we overcome a long‐standing problem with the ortho‐C?H activation of arylphosphines in a catalytic fashion. In particular, we developed a rhodium‐catalyzed ortho‐selective C?H borylation of various commercially available arylphosphines with B2pin2 through PIII‐chelation‐assisted C?H activation. This discovery is suggestive of a generic platform that could enable the late‐stage modification of readily accessible arylphosphines. 相似文献
5.
Luo‐Yan Liu Jennifer X. Qiao Kap‐Sun Yeung William R. Ewing Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2020,59(33):13831-13835
Fluorine is known to promote ortho‐C?H metalation. Based upon this reactivity, we employed an activated norbornene that traps the ortho‐palladation intermediate and is then relayed to the meta position, leading to meta‐selective C?H arylation of fluoroarenes. Deuterium experiment suggests that this meta‐arylation is initiated by ortho C?H activation and the catalytic cycle is terminated by C‐2 protonation. A dual‐ligand system is crucial for the observed high reactivity and site selectivity. Applying this approach to simple benzene or other arenes also affords arylation products with good yield and site selectivity. 相似文献
6.
Kazuishi Fukuda Nobuharu Iwasawa Jun Takaya 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(9):2876-2879
Efficient, phosphine‐directed ortho C?H borylation of arylphosphine derivatives was achieved using Ru catalysts for the first time. The reaction is applicable to various tertiary arylphosphine and arylphosphinite derivatives to give (o‐borylaryl)phosphorus compounds in high yields. This reaction enables easy access to a variety of functionalized phosphine ligands and ambiphilic phosphine boronate compounds, thus realizing a new late‐stage modification of phosphorus compounds. 相似文献
7.
Abolghasem Bakhoda Quan Jiang Yosra M. Badiei Jeffery A. Bertke Thomas R. Cundari Timothy H. Warren 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3459-3463
Undirected C(sp3)?H functionalization reactions often follow site‐selectivity patterns that mirror the corresponding C?H bond dissociation energies (BDEs). This often results in the functionalization of weaker tertiary C?H bonds in the presence of stronger secondary and primary bonds. An important, contemporary challenge is the development of catalyst systems capable of selectively functionalizing stronger primary and secondary C?H bonds over tertiary and benzylic C?H sites. Herein, we report a Cu catalyst that exhibits a high degree of primary and secondary over tertiary C?H bond selectivity in the amidation of linear and cyclic hydrocarbons with aroyl azides ArC(O)N3. Mechanistic and DFT studies indicate that C?H amidation involves H‐atom abstraction from R‐H substrates by nitrene intermediates [Cu](κ2‐N,O‐NC(O)Ar) to provide carbon‐based radicals R. and copper(II)amide intermediates [CuII]‐NHC(O)Ar that subsequently capture radicals R. to form products R‐NHC(O)Ar. These studies reveal important catalyst features required to achieve primary and secondary C?H amidation selectivity in the absence of directing groups. 相似文献
8.
Jompol Thongpaen Romane Manguin Vincent Dorcet Thomas Vives Carine Duhayon Marc Mauduit Olivier Basl 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(43):15388-15392
An efficient visible light induced rhodium(I)‐catalyzed regioselective borylation of aromatic C?H bonds is reported. The photocatalytic system is based on a single NHC?RhI complex capable of both harvesting visible light and enabling the bond breaking/forming at room temperature. The chelating nature of the NHC‐carboxylate ligand was critical to ensure the stability of the RhI complex and to provide excellent photocatalytic activities. Experimental mechanistic studies evidenced a photooxidative ortho C?H bond addition upon irradiation with blue LEDs, leading to a cyclometalated RhIII‐hydride intermediate. 相似文献
9.
Site‐Selective CH Borylation of Quinolines at the C8 Position Catalyzed by a Silica‐Supported Phosphane–Iridium System
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Shota Konishi Dr. Soichiro Kawamorita Dr. Tomohiro Iwai Prof. Patrick G. Steel Prof. Dr. Todd B. Marder Prof. Dr. Masaya Sawamura 《化学:亚洲杂志》2014,9(2):434-438
Site‐selective C? H borylation of quinoline derivatives at the C8 position has been achieved by using a heterogeneous Ir catalyst system based on a silica‐supported cage‐type monophosphane ligand SMAP. The efficient synthesis of a corticotropin‐releasing factor1 (CRF1) receptor antagonist based on a late‐stage C? H borylation strategy demonstrates the utility of the C8 borylation reaction. 相似文献
10.
Caleb Karmel Camille Z. Rubel Elena V. Kharitonova John F. Hartwig 《Angewandte Chemie (International ed. in English)》2020,59(15):6074-6081
The steric effects of substituents on five‐membered rings are less pronounced than those on six‐membered rings because of the difference in bond angles. Thus, the regioselectivities of reactions of five‐membered heteroarenes that occur with selectivities dictated by steric effects, such as the borylation of C?H bonds, have been poor in many cases. We report that the silylation of five‐membered‐ring heteroarenes occurs with high sterically derived regioselectivity when catalyzed by the combination of [Ir(cod)(OMe)]2 (cod=1,5‐cyclooctadiene) and a phenanthroline ligand or a new pyridyl‐imidazoline ligand that further increases the regioselectivity. The silylation reactions with these catalysts produce high yields of heteroarylsilanes from functionalization at the most sterically accessible C?H bonds of these rings under conditions that the borylation of C?H bonds with previously reported catalysts formed mixtures of products or products that are unstable. The heteroarylsilane products undergo cross‐coupling reactions and substitution reactions with ipso selectivity to generate heteroarenes that bear halogen, aryl, and perfluoroalkyl substituents. 相似文献
11.
Annulation of Alkynyl Aryl Ethers with Allyl Pivalates To Give 2,3‐Bismethylenechromanes through Double C−H Bond Cleavage
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Dr. Yasunori Minami Megumi Sakai Tomohiro Anami Prof. Dr. Tamejiro Hiyama 《Angewandte Chemie (International ed. in English)》2016,55(30):8701-8705
The treatment of silylethynyloxyarenes with allylic pivalates in the presence of a palladium catalyst led to efficient C?H bond cleavage in both substrates and a novel annulation reaction to give 2,3‐bismethylenechromanes. When ortho‐allylated silylethynyloxybenzenes were used as the substrates, the same products were obtained. This result shows that site‐selective intramolecular hydrovinylation is involved in the annulation reaction. The synthetic utility of the products was demonstrated by the construction of condensed polycycles. 相似文献
12.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(6):1517-1521
An iridium/bipyridine‐catalyzed ortho ‐selective C−H borylation of aryl sulfides was developed. High ortho ‐selectivity was achieved by a Lewis acid–base interaction between a boryl group of the ligand and a sulfur atom of the substrate. This is the first example of a catalytic and regioselective C−H transformation controlled by a Lewis acid–base interaction between a ligand and a substrate. The C−H borylation reaction could be conducted on a gram scale, and with a bioactive molecule as a substrate, demonstrating its applicability to late‐stage regioselective C−H borylation. A bioactive molecule was synthesized from an ortho ‐borylated product by converting the boryl and methylthio groups of the product. 相似文献
13.
Ortho‐Functionalized Aryltetrazines by Direct Palladium‐Catalyzed C−H Halogenation: Application to Fast Electrophilic Fluorination Reactions
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Christelle Testa Élodie Gigot Semra Genc Dr. Richard Decréau Dr. Julien Roger Prof. Dr. Jean‐Cyrille Hierso 《Angewandte Chemie (International ed. in English)》2016,55(18):5555-5559
A general catalyzed direct C?H functionalization of s‐tetrazines is reported. Under mild reaction conditions, N‐directed ortho‐C?H activation of tetrazines allows the introduction of various functional groups, thus forming carbon–heteroatom bonds: C?X (X=I, Br, Cl) and C?O. Based on this methodology, we developed electrophilic mono‐ and poly‐ortho‐fluorination of tetrazines. Microwave irradiation was optimized to afford fluorinated s‐aryltetrazines, with satisfactory selectivity, within only ten minutes. This work provides an efficient and practical entry for further accessing highly substituted tetrazine derivatives (iodo, bromo, chloro, fluoro, and acetate precursors). It gives access to ortho‐functionalized aryltetrazines which are difficult to obtain by classical Pinner‐like syntheses. 相似文献
14.
Stereoselective CH Borylations of Cyclopropanes and Cyclobutanes with Silica‐Supported Monophosphane–Ir Catalysts
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Ryo Murakami Kiyoshi Tsunoda Dr. Tomohiro Iwai Prof. Dr. Masaya Sawamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(41):13127-13131
Heteroatom‐directed C?H borylation of cyclopropanes and cyclobutanes was achieved with silica‐supported monophosphane–Ir catalysts. Borylation occurred at the C?H bonds located γ to the directing N or O atoms with exceptional cis stereoselectivity relative to the directing groups. This protocol was applied to the borylation of a tertiary C?H bond of a ring‐fused cyclopropane. 相似文献
15.
Catalyst‐Controlled Regiodivergent CH Borylation of Multifunctionalized Heteroarenes by Using Iridium Complexes
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Dr. Ikuo Sasaki Jumpei Taguchi Shotaro Hiraki Prof. Dr. Hajime Ito Dr. Tatsuo Ishiyama 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9236-9241
The regiodivergent C?H borylation of 2,5‐disubstituted heteroarenes with bis(pinacolato)diboron was achieved by using iridium catalysts formed in situ from [Ir(OMe)(cod)]2/dtbpy (cod=1,5‐cyclooctadiene, dtbpy: 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine) or [Ir(OMe)(cod)]2/2 AsPh3. When [Ir(OMe)(cod)]2/dtbpy was used as the catalyst, borylation at the 4‐position proceeded selectively to afford 4‐borylated products in high yields (dtbpy system A). The regioselectivity changed when the [Ir(OMe)(cod)]2/2 AsPh3 catalyst was used; 3‐borylated products were obtained in high yields with high regioselectivity (AsPh3 system B). The regioselectivity of borylation was easily controlled by changing the ligands. This reaction was used in the syntheses of two different bioactive compound analogues by using the same starting material. 相似文献
16.
Dehydrogenative Carbon–Carbon Bond Formation Using Alkynyloxy Moieties as Hydrogen‐Accepting Directing Groups
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Dr. Yasunori Minami Tatsuro Kodama Prof. Dr. Tamejiro Hiyama 《Angewandte Chemie (International ed. in English)》2015,54(40):11813-11816
In the presence of a catalyst system consisting of Pd(OAc)2, PCy3, and Zn(OAc)2, the reaction of alkynyl aryl ethers with bicycloalkenes, α,ß‐unsaturated esters, or heteroarenes results in the site‐selective cleavage of two C? H bonds followed by the formation of C? C bonds. In all cases, the alkynyloxy group acts as a directing group for the activation of an ortho C? H bond and as a hydrogen acceptor, thus rendering the use of additives such as an oxidant or base unnecessary. 相似文献
17.
Pidiyara Karishma Devesh S. Agarwal Biswajit Laha Sanjay K. Mandal Rajeev Sakhuja 《化学:亚洲杂志》2019,14(23):4274-4288
A direct ortho‐Csp2‐H acylmethylation of 2‐aryl‐2,3‐dihydrophthalazine‐1,4‐diones with α‐carbonyl sulfoxonium ylides is achieved through a RuII‐catalyzed C?H bond activation process. The protocol featured high functional group tolerance on the two substrates, including aryl‐, heteroaryl‐, and alkyl‐substituted α‐carbonyl sulfoxonium ylides. Thereafter, 2‐(ortho‐acylmethylaryl)‐2,3‐dihydrophthalazine‐1,4‐diones were used as potential starting materials for the expeditious synthesis of 6‐arylphthalazino[2,3‐a]cinnoline‐8,13‐diones and 5‐acyl‐5,6‐dihydrophthalazino[2,3‐a]cinnoline‐8,13‐diones under Lawesson's reagent and BF3?OEt2 mediated conditions, respectively. Of these, the BF3?OEt2‐mediated cyclization proceeded in DMSO as a solvent and a methylene source via dual C?C and C?N bond formations. 相似文献
18.
Catalytic Borylation of SCF3‐Functionalized Arenes by Rhodium(I) Boryl Complexes: Regioselective CH Activation at the ortho‐Position
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Dipl.‐Chem. Sabrina I. Kalläne Prof. Dr. Thomas Braun 《Angewandte Chemie (International ed. in English)》2014,53(35):9311-9315
An unprecedented reaction pathway for the borylation of SCF3‐containing arenes using [Rh(Bpin)(PEt3)3] (pin=pinacolato) is reported. Catalytic processes were developed and the functionalizations proceed under mild reaction conditions. The C? H activations occur with a unique regioselectivity for the position ortho to the SCF3 group, which apparently serves as directing group. Borylated SCF3 compounds can serve as versatile building blocks. 相似文献
19.
Room‐Temperature ortho‐Alkoxylation and ‐Halogenation of N‐Tosylbenzamides by Using Palladium(II)‐Catalyzed CH Activation
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Dr. Florent Péron Dr. Christine Fossey Prof. Dr. Jana Sopkova‐de Oliveira Santos Dr. Thomas Cailly Prof. Dr. Frédéric Fabis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(24):7507-7513
The N‐tosylcarboxamide group can direct the room‐temperature palladium‐catalyzed C?H alkoxylation and halogenation of substituted arenes in a simple and mild procedure. The room‐temperature stoichiometric cyclopalladation of N‐tosylbenzamide was first studied, and the ability of the palladacycle to react with oxidants to form C?X and C?O bonds under mild conditions was demonstrated. The reaction conditions were then adapted to promote room‐temperature ortho‐alkoxylations and ortho‐halogenations of N‐tosylbenzamides using palladium as catalyst. The scope and limitation of both alkoxylations and halogenations was studied and the subsequent functional transformation of the N‐tosylcarboxamide group through nucleophilic additions was evaluated. This methodology offers a simple and mild route to diversely functionalized arenes. 相似文献
20.
Highly Stereoselective β‐Mannopyranosylation via the 1‐α‐Glycosyloxy‐isochromenylium‐4‐gold(I) Intermediates
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While the gold(I)‐catalyzed glycosylation reaction with 4,6‐O‐benzylidene tethered mannosyl ortho‐alkynylbenzoates as donors falls squarely into the category of the Crich‐type β‐selective mannosylation when Ph3PAuOTf is used as the catalyst, in that the mannosyl α‐triflates are invoked, replacement of the ?OTf in the gold(I) complex with less nucleophilic counter anions (i.e., ?NTf2, ?SbF6, ?BF4, and ?BAr4F) leads to complete loss of β‐selectivity with the mannosyl ortho‐alkynylbenzoate β‐donors. Nevertheless, with the α‐donors, the mannosylation reactions under the catalysis of Ph3PAuBAr4F (BAr4F=tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate) are especially highly β‐selective and accommodate a broad scope of substrates; these include glycosylation with mannosyl donors installed with a bulky TBS group at O3, donors bearing 4,6‐di‐O‐benzoyl groups, and acceptors known as sterically unmatched or hindered. For the ortho‐alkynylbenzoate β‐donors, an anomerization and glycosylation sequence can also ensure the highly β‐selective mannosylation. The 1‐α‐mannosyloxy‐isochromenylium‐4‐gold(I) complex ( Cα ), readily generated upon activation of the α‐mannosyl ortho‐alkynylbenzoate ( 1 α ) with Ph3PAuBAr4F at ?35 °C, was well characterized by NMR spectroscopy; the occurrence of this species accounts for the high β‐selectivity in the present mannosylation. 相似文献