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1.
Manh V. Pham Nicolai Cramer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(13):3552-3555
Larger condensed arenes are of interest owing to their electro‐ and photochemical properties. An efficient synthesis is the catalyzed aromatic annulation of a smaller arene with two alkyne molecules. Besides difunctionalized starting materials, directed C H functionalization can be used for such aromatic homologation. However, thus far the requirement of either pre‐functionalized substrates or suitable directing groups were limiting this approach. Herein, we describe a rhodium(III)‐catalyzed method allowing the use of completely unbiased arenes and internal alkynes. The reaction works best with copper(II) 2‐ethylhexanoate and decabromodiphenyl ether as the oxidant combination. This aromatic annulation tolerates a variety of functional groups and delivers homologated condensed arenes. Aside from simple benzenes, naphthalenes and higher condensed arenes provide access to highly substituted and highly soluble acenes structures having important electronic and photophysical properties. 相似文献
2.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7703-7708
Palladium‐catalyzed base‐selective annulation of dibromonaphthalimide to different aryl boronate esters by combined Suzuki–Miyaura cross‐coupling and direct C−H arylation afforded a series of new five‐ and six‐membered ring annulated electron‐poor polycyclic aromatic hydrocarbons. Cesium carbonate (Cs2CO3) as auxiliary base in these C−C coupling cascade reactions led exclusively to six‐membered ring annulation, while the use of organic base diazabicycloundecene (DBU) afforded the corresponding five‐membered ring annulated products. This base‐dependent selective mode of annulation is attributed to different mechanistic pathways directed by the applied base. The selective annulation was revealed by single crystal X‐ray analysis of the respective five‐ and six‐membered ring annulated products. The optical and redox properties of the new polycyclic aromatic dicarboximides were characterized by UV/Vis absorption and fluorescence spectroscopy and cyclic voltammetry. 相似文献
3.
Wei‐Jun Kong Zhigao Shen Lars H. Finger Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2020,59(14):5551-5556
Nitrogen‐doped polycyclic aromatic hydrocarbons (aza‐PAHs) have found broad applications in material sciences. Herein, a modular electrochemical synthesis of aza‐PAHs was developed via a rhodium‐catalyzed cascade C?H activation and alkyne annulation. A multifunctional O‐methylamidoxime enabled the high chemo‐ and regioselectivity. The isolation of two key rhodacyclic intermediates made it possible to delineate the exact order of three C?H activation steps. In addition, the metalla‐electrocatalyzed multiple C?H transformation is characterized by unique functional group tolerance, including highly reactive iodo and azido groups. 相似文献
4.
Iron‐Carbonyl‐Catalyzed Redox‐Neutral [4+2] Annulation of N−H Imines and Internal Alkynes by C−H Bond Activation 下载免费PDF全文
Teng Jia Chongyang Zhao Dr. Ruoyu He Prof. Dr. Hui Chen Prof. Dr. Congyang Wang 《Angewandte Chemie (International ed. in English)》2016,55(17):5268-5271
Stoichiometric C?H bond activation of arenes mediated by iron carbonyls was reported by Pauson as early as in 1965, yet the catalytic C?H transformations have not been developed. Herein, an iron‐catalyzed annulation of N?H imines and internal alkynes to furnish cis‐3,4‐dihydroisoquinolines is described, and represents the first iron‐carbonyl‐catalyzed C?H activation reaction of arenes. Remarkablely, this is also the first redox‐neutral [4+2] annulation of imines and alkynes proceeding by C?H activation. The reaction also features only cis stereoselectivity and excellent atom economy as neither base, nor external ligand, nor additive is required. Experimental and theoretical studies reveal an oxidative addition mechanism for C?H bond activation to afford a dinuclear ferracycle and a synergetic diiron‐promoted H‐transfer to the alkyne as the turnover‐determining step. 相似文献
5.
Cobalt‐Catalyzed Oxidative Annulation of Nitrogen‐Containing Arenes with Alkynes: An Atom‐Economical Route to Heterocyclic Quaternary Ammonium Salts 下载免费PDF全文
Sekar Prakash Dr. Krishnamoorthy Muralirajan Prof. Dr. Chien‐Hong Cheng 《Angewandte Chemie (International ed. in English)》2016,55(5):1844-1848
Four cobalt‐catalyzed oxidative annulation reactions of nitrogen‐containing arenes with alkynes proceeds by C?H activation, thus leading to biologically useful quaternary ammonium salts, including pyridoisoquinolinium, cinnolinium, isoquinolinium, and quinolizinium salts, in high yields. The results are comparable to those reactions catalyzed by rhodium and ruthenium complexes. The transformation of the salts into various N‐heterocycles has also been demonstrated. 相似文献
6.
Sulfur‐Annulated Hexa‐peri‐hexabenzocoronene Decorated with Phenylthio Groups at the Periphery 下载免费PDF全文
Dr. Yuan‐Zhi Tan Dr. Silvio Osella Yi Liu Bo Yang Prof. Dr. David Beljonne Prof. Dr. Xinliang Feng Prof. Dr. Klaus Müllen 《Angewandte Chemie (International ed. in English)》2015,54(10):2927-2931
The chemical nature of the edge periphery essentially determines the physical properties of graphene. As a molecular‐level model system, large polycyclic aromatic hydrocarbons, that is, so‐called nanographenes, can be chemically modified through either edge functionalization or doping with heteroatoms. Although the synthetic methods for edge substitution are well‐developed, incorporation with heteroatoms by the bay annulation of large PAHs remains an enormous challenge. In this study, we present a feasible peripheral sulfur annulation of hexa‐peri‐hexabenzocoronene (HBC) by thiolation of perchlorinated HBC. The tri‐sulfur‐annulated HBC and di‐sulfur‐annulated HBC decorated with phenylthio groups were obtained and characterized by X‐ray diffraction, revealing their distinct sulfur‐annulated peripheral structure. Associated with theoretical calculations, we propose that the regioselective sulfur annulation results from the minimization of strain in the aromatic backbone. We further demonstrate the structure‐correlated property modulation by sulfur annulation, manifested by a decrease in band gap and tunable redox activity. 相似文献
7.
Highly Regio‐, Diastereo‐, and Enantioselective Gold(I)‐Catalyzed Intermolecular Annulations with N‐Allenamides at the Proximal CC Bond 下载免费PDF全文
Yidong Wang Peichao Zhang Deyun Qian Prof. Dr. Junliang Zhang 《Angewandte Chemie (International ed. in English)》2015,54(49):14849-14852
A highly enantioselective gold(I)‐catalyzed intermolecular annulation of 2‐(1‐alkynyl)‐2‐alken‐1‐ones with N‐allenamides is presented. The present work represents the first example of a gold‐catalyzed annulation with the proximal C?C bond of an N‐allenamide, and is distinctly different from the previously observed annulations at the distal C?C bond. Interestingly, both enantiomers of the products could be obtained in good yields with high regio‐, diastereo‐, and enantioselectivity by using either diastereomer of a binol‐derived phosphoramidite as a chiral ligand. 相似文献
8.
Rhodium(III)‐Catalyzed Intramolecular Redox‐Neutral Annulation of Tethered Alkynes: Formal Total Synthesis of (±)‐Goniomitine 下载免费PDF全文
Dr. Bing Zhou Dr. Juanjuan Du Dr. Yaxi Yang Prof. Yuanchao Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12768-12772
A RhIII‐catalyzed intramolecular redox‐neutral atom‐economic annulation of a tethered alkyne has been developed to efficiently construct 2‐amidealkyl indoles with completely reversed regioselectivity by a C?H activation pathway. Furthermore, using the RhIII‐catalyzed C?H activation/annulation as a key step, a one‐pot synthesis of pyrido[1,2‐a]indoles has also been developed and applied to a highly efficient formal total synthesis of (±)‐goniomitine. 相似文献
9.
One‐pot Annulation for Biaryl‐fused Monocarba‐closo‐dodecaborate through Aromatic B−H Bond Disconnection 下载免费PDF全文
Gaku Akimoto Mai Otsuka Dr. Kazunori Miyamoto Dr. Atsuya Muranaka Dr. Daisuke Hashizume Dr. Ryo Takita Prof. Dr. Masanobu Uchiyama 《化学:亚洲杂志》2018,13(8):913-917
We have developed a one‐pot annulation reaction of monocarba‐closo‐dodecaborate with cyclic diaryliodonium salts to afford biaryl‐fused derivatives. Aryl functionalities are introduced at both the 1‐carbon and unreactive ortho‐boron vertices of the “σ‐aromatic” carborane cage without the need for pre‐functionalization. DFT calculations revealed that the palladium‐catalyzed C?B bond‐formation step in this process proceeds through a concerted metalation–deprotonation (CMD)‐type pathway for the B?H bond disconnection on the aromatic cage, though such bonds are generally regarded as hydridic. 相似文献
10.
Diastereoselective [3+2] Annulation of Aromatic/Vinylic Amides with Bicyclic Alkenes through Cobalt‐Catalyzed C−H Activation and Intramolecular Nucleophilic Addition 下载免费PDF全文
Dr. Parthasarathy Gandeepan Dr. Pachaiyappan Rajamalli Prof. Dr. Chien‐Hong Cheng 《Angewandte Chemie (International ed. in English)》2016,55(13):4308-4311
A highly diastereoselective method for the synthesis of dihydroepoxybenzofluorenone derivatives from aromatic/vinylic amides and bicyclic alkenes is described. This new transformation proceeds through cobalt‐catalyzed C?H activation and intramolecular nucleophilic addition to the amide functional group. Transition‐metal‐catalyzed C?H activation reactions of secondary amides with alkenes usually lead to [4+2] or [4+1] annulation; to the best of our knowledge, this is the first time that a [3+2] cycloaddition is described in this context. The reaction proceeds under mild conditions and tolerates a wide range of functional groups. Mechanistic studies imply that the C?H bond cleavage may be the rate‐limiting step. 相似文献
11.
Palladium‐Catalyzed Regioselective Aromatic Extension of Internal Alkynes through a Norbornene‐Controlled Reaction Sequence 下载免费PDF全文
Dr. Qingyang Zhao Dr. Wai Chung Fu Prof. Dr. Fuk Yee Kwong 《Angewandte Chemie (International ed. in English)》2018,57(13):3381-3385
A regioselective aromatic π‐extension reaction of internal alkynes is reported. The proposed method employs three easily available components, namely aryl halides, 2‐haloarylcarboxylic acids, and disubstituted acetylenes. The transformation is driven by a controlled reaction sequence of C?H activation, decarboxylation, and annulation to give poly(hetero)aromatic compounds in a site‐selective fashion. Unlike in previously reported palladium‐catalyzed three‐component annulations, alkyne carbopalladation is the last step of this tandem reaction. 相似文献
12.
Prof. Dr. Masaki Shimizu Yosuke Tomioka Dr. Ikuhiro Nagao Tsugumi Kadowaki Prof. Dr. Tamejiro Hiyama 《化学:亚洲杂志》2012,7(7):1644-1651
(Z)‐1,2‐Diaryl‐1,2‐bis(pinacolatoboryl)ethenes underwent double‐cross‐coupling reactions with 1‐bromo‐2‐[(Z)‐2‐bromoethenyl]arenes in the presence of [Pd(PPh3)4] as a catalyst and 3 M aqueous Cs2CO3 as a base in THF at 80 °C. The double‐coupling reaction gave multisubstituted naphthalenes in good to high yields. Annulation of 1,2‐bis(pinacolatoboryl)arenes with bromo(bromoethenyl)arenes in the presence of a catalyst system that consisted of [Pd2(dba)3] (dba=dibenzylideneacetone) and 2‐dicyclohexylphosphino‐2′,6′‐dimethoxybiphenyl (SPhos) under the same conditions produced fused phenanthrenes in good to high yields. The first annulation coupling occurred regiospecifically at the bromoethenyl moiety. This procedure is applicable to the facile synthesis of polysubstituted anthracenes, benzothiophenes, and dibenzoanthracenes through a double annulation pathway by using the corresponding dibromobis[(Z)‐2‐bromoethenyl]benzenes as diboryl coupling partners. 相似文献
13.
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
14.
Metal‐Free Annulation of Arenes with 2‐Aminopyridine Derivatives: The Methyl Group as a Traceless Non‐Chelating Directing Group 下载免费PDF全文
Srimanta Manna Dr. Kiran Matcha Dr. Andrey P. Antonchick 《Angewandte Chemie (International ed. in English)》2014,53(31):8163-8166
A novel annulation reaction between 2‐aminopyridine derivatives and arenes under metal‐free conditions is described. The presented intermolecular transformation provided straightforward access to the important pyrido[1,2‐a]benzimidazole scaffold under mild reaction conditions. The unprecedented application of the methyl group of methylbenzenes as a traceless, non‐chelating, and highly regioselective directing group is reported. 相似文献
15.
Dr. Qingzhen Yu Le'an Hu Yue Wang Shasha Zheng Prof. Dr. Jianhui Huang 《Angewandte Chemie (International ed. in English)》2015,54(50):15284-15288
A Ru‐catalyzed direct C? H activation/meta‐bromination of arenes bearing pyridyl, pyrimidyl, and pyrazolyl directing groups has been developed. A series of bromo aryl pyridines and pyrimidines have been synthesized, and further coupling reactions have also been demonstrated for a number of representative functionalized arenes. Preliminary mechanistic studies have revealed that this reaction may proceed through radical‐mediated bromination when NBS is utilized as the bromine source. This type of transformation has opened up a new direction for the radical non‐ipso functionalization of metal with regard to future C? H activation development that would allow the remote functionalization of aromatic systems. 相似文献
16.
Skeletal Rearrangement in the ZnII‐Catalyzed [4+2]‐Annulation of Disubstituted N‐Hydroxy Allenylamines with Nitrosoarenes to Yield Substituted 1,2‐Oxazinan‐3‐one Derivatives 下载免费PDF全文
Pankaj Sharma Prof. Dr. Rai‐Shung Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15881-15887
This work reports zinc‐catalyzed [4+2]‐annulation reactions of disubstituted N‐hydroxy allenylamines with nitrosoarenes to afford substituted 1,2‐oxazinan‐3‐ones with a skeletal rearrangement. This annulation is applicable to a reasonable scope of allenylamines and nitrosoarenes. Our control experiments indicate that nitrosobenzene can also implement this annulation through a radical annulation path, but with poor efficiency. Zn(OTf)2 or AgOTf greatly improves the efficiency of this [4+2]‐annulation; the effect of these metal species is discussed in detail. 相似文献
17.
Nickel‐Catalyzed Difluoroalkylation of (Hetero)Arylborons with Unactivated 1‐Bromo‐1,1‐difluoroalkanes 下载免费PDF全文
Yu‐Lan Xiao Qiao‐Qiao Min Chang Xu Dr. Ruo‐Wen Wang Prof. Dr. Xingang Zhang 《Angewandte Chemie (International ed. in English)》2016,55(19):5837-5841
A nickel‐catalyzed cross‐coupling between (hetero)arylborons and unactivated 1‐bromo‐1,1‐difluoroalkanes has been developed. The use of two ligands (a bidentate bipyridine‐based ligand, 4,4′‐ditBu‐bpy, and a monodentate pyridine‐based ligand, DMAP) offers a highly efficient nickel‐based catalytic system to prepare difluoroalkylated arenes which have important applications in medicinal chemistry. 相似文献
18.
Chao Feng Prof. Dr. Teck‐Peng Loh 《Angewandte Chemie (International ed. in English)》2014,53(10):2722-2726
The rhodium(III)‐catalyzed ortho C? H alkynylation of non‐electronically activated arenes is disclosed. This process features a straightforward and highly effective protocol for the synthesis of functionalized alkynes and represents the first example of merging a hypervalent iodine reagent with rhodium(III) catalysis. Notably, this reaction proceeds at room temperature, tolerates a variety of functional groups, and more importantly, exhibits high selectivity for monoalkynylation. 相似文献
19.
Gold‐Catalyzed Regiospecific C−H Annulation of o‐Ethynylbiaryls with Anthranils: π‐Extension by Ring‐Expansion En Route to N‐Doped PAHs 下载免费PDF全文
Zhongyi Zeng Hongming Jin Dr. Kohei Sekine Dr. Matthias Rudolph Frank Rominger Prof. Dr. A. Stephen K. Hashmi 《Angewandte Chemie (International ed. in English)》2018,57(23):6935-6939
We describe a novel, short, and flexible approach to diverse N‐doped polycyclic aromatic hydrocarbons (PAHs) through gold‐catalyzed π‐extension of anthranils with o‐ethynylbiaryls as reagents. This strategy uses easily accessible starting materials, is simple due to high step and atom economy, and shows good functional‐group compatibility as well as scale‐up potential. Mechanistically, the tandem reaction is proposed to involve a nucleophilic addition/ring opening/regiospecific C?H annulation/protodeauration sequence terminated by a Friedel–Crafts‐type cyclization. Photophysical studies of the products indicated violet‐blue fluorescence emission with quantum yields up to 0.45. 相似文献
20.
Phase‐Transfer‐Catalyzed Asymmetric SNAr Reaction of α‐Amino Acid Derivatives with Arene Chromium Complexes 下载免费PDF全文
Prof. Dr. Seiji Shirakawa Kenichiro Yamamoto Prof. Dr. Keiji Maruoka 《Angewandte Chemie (International ed. in English)》2015,54(3):838-840
Although phase‐transfer‐catalyzed asymmetric SNAr reactions provide unique contribution to the catalytic asymmetric α‐arylations of carbonyl compounds to produce biologically active α‐aryl carbonyl compounds, the electrophiles were limited to arenes bearing strong electron‐withdrawing groups, such as a nitro group. To overcome this limitation, we examined the asymmetric SNAr reactions of α‐amino acid derivatives with arene chromium complexes derived from fluoroarenes, including those containing electron‐donating substituents. The arylation was efficiently promoted by binaphthyl‐modified chiral phase‐transfer catalysts to give the corresponding α,α‐disubstituted α‐amino acids containing various aromatic substituents with high enantioselectivities. 相似文献