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1.
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
2.
Andreas B. Bellan Paul Knochel 《Angewandte Chemie (International ed. in English)》2019,58(6):1838-1841
Substituted arenes flanked by two bulky triethylsilyl groups were regiospecifically lithiated at the 5‐position with nBuLi?PMDTA at 25 °C. The resulting aryllithiums reacted with a broad range of electrophiles such as ketones, isocyanates, Weinreb amides, allyl bromides, and CO2 at 25 °C. These bis‐silylated arenes were then converted in simple reaction sequences into silyl‐free tetrasubstituted arenes. This remote lithiation was extended to 2,6‐bis(triethylsilyl)pyridine as well as 3,3′‐bis(triethylsilyl)biphenyl. 相似文献
3.
《中国化学》2018,36(2):143-146
Although bromodifluoromethane (BrCF2H) is a simple and readily available fluorine source, direct formation of difluoromethylated arenes with BrCF2H has not been reported. Herein, we describe an efficient method to access difluoromethylated arenes through a nickel‐catalyzed difluoromethylation of arylboronic acids with BrCF2H. The reaction exhibits high efficiency, good functional group tolerance and broad substrate scope, thus providing an efficient route for applications in drug discovery and development. Preliminary mechanistic studies reveal that a difluoromethyl radical is involved in the reaction. 相似文献
4.
Laure Monnereau Dr. David Sémeril Dr. Dominique Matt Dr. Loïc Toupet Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(30):9237-9247
Five conical calix[4]arenes that have a PPh2 group as the sole functional group anchored at their upper rim were assessed in palladium‐catalysed cross‐coupling reactions of phenylboronic acid with aryl halides (dioxane, 100 °C, NaH). With arylbromides, remarkably high activities were obtained with the catalytic systems remaining stable for several days. The performance of the ligands is comparable to a Buchwald‐type triarylphosphane, namely, (2′‐methyl[1,1′‐biphenyl]‐2‐yl)diphenylphosphane, which in contrast to the calixarenyl phosphanes tested may display chelating behaviour in solution. With the fastest ligand, 5‐diphenylphosphanyl‐25,26,27,28‐tetra(p‐methoxy)benzyloxy‐calix[4]arene ( 8 ), the reaction turnover frequency for the arylation of 4‐bromotoluene was 321 000 versus 214 000 mol(ArBr).mol(Pd)?1. h?1 for the reference ligand. The calixarene ligands were also efficient in Suzuki cross‐coupling reactions with aryl chlorides. Thus, by using 1 mol % of [Pd(OAc)2] associated with one of the phosphanes, full conversion of the deactivated arenes 4‐chloroanisole and 4‐chlorotoluene was observed after 16 h. The high performance of the calixarenyl–phosphanes in Suzuki–Miyaura coupling of aryl bromides possibly relies on their ability to stabilise a monoligand [Pd0L(ArBr)] species through supramolecular binding of the Pd‐bound arene inside the calixarene cavity. 相似文献
5.
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
6.
David Lebœuf Dr. Laura Iannazzo Anaïs Geny Max Malacria Prof. Dr. K. Peter C. Vollhardt Prof. Dr. Corinne Aubert Dr. Vincent Gandon Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(29):8904-8913
A variety of 1,6‐heptadiynes and certain borylalkynes co‐oligomerize with enol ethers in the presence of [CpCo(C2H4)2] (Cp=cyclopentadienyl) to furnish the hitherto elusive acyclic 2:1 products, 1,3,5‐trien‐1‐ol ethers, in preference to or in competition with the alternative pathway that leads to the standard [2+2+2] cycloadducts, 5‐alkoxy‐1,3‐cyclohexadienes. Minor variations, such as lengthening the diyne tether, cause reversion to the standard mechanism. The trienes, including synthetically potent borylated derivatives, are generated with excellent levels of chemo‐, regio‐, and diastereoselectivity, and are obtained directly by decomplexation of the crude mixtures during chromatography. The cyclohexadienes are isolated as the corresponding dehydroalkoxylated arenes. In one example, even ethene functions as a linear cotrimerization partner. The alkoxytrienes are thermally labile with respect to 6π‐electrocyclization–elimination to give the same arenes that are the products of cycloaddition. The latter, regardless of the mechanism of their formation, can be viewed as the result of a formal [2+2+2] cyclization of the starting alkynes with acetylene. One‐pot conditions for the exclusive formation of arenes are developed. DFT computations indicate that cyclohexadiene and triene formation share a common intermediate, a cobaltacycloheptadiene, from which reductive elimination and β‐hydride elimination compete. 相似文献
7.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(46):14630-14634
By simple ligand exchange of the cationic transition‐metal complexes [(Cp*)M(acetone)3](OTf)2 (Cp*=pentamethylcyclopentadienyl and M=Ir or Rh) with pillar[5]arene, mono‐ and polynuclear pillar[5]arenes, a new class of metalated host molecules, is prepared. Single‐crystal X‐ray analysis shows that the charged transition‐metal cations are directly bound to the outer π‐surface of aromatic rings of pillar[5]arene. One of the triflate anions is deeply embedded within the cavity of the trinuclear pillar[5]arenes, which is different to the host–guest behavior of most pillar[5]arenes. DFT calculation of the electrostatic potential revealed that the metalated pillar[5]arenes featured an electron‐deficient cavity due to the presence of the electron‐withdrawing transition metals, thus allowing encapsulation of electron‐rich guests mainly driven by anion–π interactions. 相似文献
8.
Copper‐Mediated Aromatic 1,1‐Difluoroethylation with (1,1‐Difluoroethyl)trimethylsilane (TMSCF2CH3) 下载免费PDF全文
Xinjin Li Dr. Jingwei Zhao Yunze Wang Jian Rong Dr. Mingyou Hu Dr. Dingben Chen Pan Xiao Dr. Chuanfa Ni Prof. Dr. Limin Wang Prof. Dr. Jinbo Hu 《化学:亚洲杂志》2016,11(12):1789-1792
A new method for the formation of 1,1‐difluoroethyl copper species (“CuCF2CH3”) with 1,1‐difluoroethylsilane (TMSCF2CH3) has been developed. The “CuCF2CH3” species can be applied to the efficient 1,1‐difluoroethylation of diaryliodonium salts under mild conditions, affording (1,1‐difluoroethyl)arenes in good to excellent yields. This convenient procedure tolerates a wide range of functional groups and thus serves as a practical synthetic tool for the introduction of CF2CH3 group(s) into complex molecules. 相似文献
9.
Room‐Temperature ortho‐Alkoxylation and ‐Halogenation of N‐Tosylbenzamides by Using Palladium(II)‐Catalyzed CH Activation 下载免费PDF全文
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
10.
Kui Wang Dr. Dong‐Sheng Guo Prof. Dr. Yu Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(28):8758-8764
The complexation‐induced critical aggregation concentrations of 1‐pyrenemethylaminium by mono‐p‐sulfonatocalix[n]arenes and bis‐p‐sulfonatocalix[n]arenes (n=4, 5) were systemically measured by fluorescence spectroscopy. In all cases, the complexation‐induced critical aggregation concentration decreases by about 3 times upon addition of p‐sulfonatocalix[n]arenes. However, the optimal molar ratios for the aggregation of 1‐pyrenemethylaminium by mono‐p‐sulfonatocalix[n]arenes and bis‐p‐sulfonatocalix[n]arenes are distinctly different: For mono‐p‐sulfonatocalix[n]arenes, the optimum mixing ratio for the aggregation of 1‐pyrenemethylaminium is 1:4 mono‐p‐sulfonatocalix[n]arenes/1‐pyrenemethylaminium, whereas only 2.5 molecules of 1‐pyrenemethylaminium can be bound by one cavity of bis‐p‐sulfonatocalix[n]arenes. The intermolecular complexation of mono‐p‐sulfonatocalix[n]arenes and bis‐p‐sulfonatocalix[n]arenes with 1‐pyrenemethylaminium led to the formation of two distinctly different nanoarchitectures, which were shown to be nanoscale vesicle and rod aggregates, respectively, by using dynamic laser scattering, TEM, and SEM. This behavior is also different from the fiber‐like aggregates with lengths of several micrometers that were formed by 1‐pyrenemethylaminium itself above its critical aggregation concentration. Furthermore, the obtained nanoaggregates exhibit benign water solubility, self‐labeled fluorescence, and, more importantly, temperature responsiveness. 相似文献
11.
Dr. Lin He Dr. Kishore Natte Dr. Jabor Rabeah Dr. Christoph Taeschler Dr. Helfried Neumann Prof. Dr. Angelika Brückner Prof. Dr. Matthias Beller 《Angewandte Chemie (International ed. in English)》2015,54(14):4320-4324
Fluorinated organic compounds are gaining increasing interest for life science applications. The replacement of hydrogen in arenes or heteroarenes by a perfluoroalkyl group has a profound influence on the physical and biological properties of such building blocks. Here, an operationally simple protocol for the direct C? H perfluoroalkylation of (hetero)arenes with RfI or RfBr has been developed, using a robust supported platinum catalyst. The ready availability of the starting materials, the excellent substrate tolerance, and the reusability of the catalyst make this method attractive for the synthesis of a variety of perfluoroalkyl‐substituted aromatic compounds. Preliminary mechanistic studies revealed the formation of radicals to be crucial in the reaction system. 相似文献
12.
Xiaoming Liu Colin A. Kilner Malcolm A. Halcrow 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(4):o218-o219
The title compound, 5‐methoxyspiro[tetracyclo[8.8.1.03,8.012,17]nonadeca‐3,5,7,12,14,16‐hexene‐19,2′‐[1,3]dioxolane], C22H24O3, exhibits a twin‐chair conformation with the aromatic rings overlying each other. Comparison of the dihedral angle between these two rings with those from previously reported [3.3]orthocyclophanes of this type suggests the presence of a weak attractive charge‐transfer interaction between the two, different, stacked arenes. 相似文献
13.
Tandem Gold/Silver‐Catalyzed Cycloaddition/Hydroarylation of 7‐Aryl‐1,6‐enynes to Form 6,6‐Diarylbicyclo[3.2.0]heptanes 下载免费PDF全文
Bradley D. Robertson Rachel E. M. Brooner Prof. Ross A. Widenhoefer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5714-5717
Mixtures of [{PCy2(o‐biphenyl)}AuCl] and AgSbF6 catalyze the tandem cycloaddition/hydroarylation of 7‐aryl‐1,6‐enynes with electron‐rich arenes to form 6,6‐diarylbicyclo[3.2.0]heptanes in good yield under mild conditions. Experimental observations point to a mechanism involving gold‐catalyzed cycloaddition followed by silver‐catalyzed hydroarylation of a bicyclo[3.2.0]hept‐1(7)‐ene intermediate. 相似文献
14.
Copper‐mediated pentafluoroethylation of arenediazonium tetrafluoroborates with tetrafluoroethylene (TFE) on‐site generated from TMSCF3 has been developed as a new method to prepare pentafluoroethyl arenes. The active pentafluoroethylation reagent “CuC2F5” is pre‐generated from CuSCN, TFE and CsF, and its generation and further reaction are strongly solvent‐dependent. This pentafluoroethylation reaction represents the first example of Sandmeyer‐type pentafluoroethylation, which exhibits good functional group tolerance and potential applications for the synthesis of complicated bioactive compounds. 相似文献
15.
Hongbo Qin Noriyuki Yamagiwa Dr. Shigeki Matsunaga Dr. Masakatsu Shibasaki Prof. Dr. 《化学:亚洲杂志》2007,2(1):150-154
Catalytic intermolecular hydroamination of vinyl arenes is described. Our initial investigation revealed that a Bi(OTf)3/[Cu(CH3CN)4]PF6 system previously developed for catalytic intermolecular hydroamination of 1,3‐dienes was suitable for hydroamination of a styrene with sulfonamides, but the substrate generality of this system was unsatisfactory. Several metals were screened to expand the substrate scope, and a new Hf(OTf)4/[Cu(CH3CN)4]PF6 system was determined to be highly suitable. The combination of Hf(OTf)4 and [Cu(CH3CN)4]PF6 efficiently promoted the hydroamination of various vinyl arenes, including less‐reactive vinyl arenes with electron‐withdrawing groups. This strategy was applied to sulfonamides, carbamates, and carboxamides, and products were obtained in up to 99 % yield with 0.3–10 mol % catalyst loading. 相似文献
16.
《化学:亚洲杂志》2017,12(19):2524-2527
The direct C−H trifluoromethylation of arenes catalyzed by graphene oxide (GO) under safe conditions is described. This strategy is metal‐free, initiator‐free, safe, and scalable. It employs a readily available CF3 source and the reaction can be easily controlled to obtain a mono‐trifluorinated product. This method opens a new avenue for GO‐catalyzed chemistry. 相似文献
17.
Dr. Kishore Natte Dr. Rajenahally V. Jagadeesh Dr. Lin He Dr. Jabor Rabeah Jianbin Chen Dr. Christoph Taeschler Dr. Stefan Ellinger Dr. Florencio Zaragoza Dr. Helfried Neumann Prof. Dr. Angelika Brückner Prof. Dr. Matthias Beller 《Angewandte Chemie (International ed. in English)》2016,55(8):2782-2786
The CF3 group is an omnipresent motif found in many pharmaceuticals, agrochemicals, catalysts, materials, and industrial chemicals. Despite well‐established trifluoromethylation methodologies, the straightforward and selective introduction of such groups into (hetero)arenes using available and less expensive sources is still a major challenge. In this regard, the selective synthesis of various trifluoromethyl‐substituted (hetero)arenes by palladium‐catalyzed C?H functionalization is herein reported. This novel methodology proceeds under comparably mild reaction conditions with good regio‐ and chemoselectivity. As examples, trifluoromethylations of biologically important molecules, such as melatonin, theophylline, caffeine, and pentoxifylline, are showcased. 相似文献
18.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(25):7257-7261
Corona[5]arenes, a novel type of macrocyclic compound that is composed of alternating heteroatoms and para ‐arylenes, were synthesized efficiently by two distinct methods. In a macrocycle‐to‐macrocycle transformation approach, S6‐corona[3]arene[3]tetrazine underwent sequential SNAr reactions with HS‐C6H4‐X‐C6H4‐SH (X=S, CH2, CMe2, SO2, and O) to produce the corresponding corona[3]arene[2]tetrazines. Different corona[3]arene[2]tetrazine compounds were also constructed in a straightforward manner by a one‐pot three‐component reaction of HS‐C6H4‐X‐C6H4‐SH (X=S, CH2, CMe2, SO2, and O) with diethyl 2,5‐dimercaptoterephthalate and 2 equiv of 3,6‐dichlorotetrazine under very mild conditions. All corona[5]arenes adopted 1,2,4‐alternate conformational structures in the crystalline state yielding similar nearly regular pentagonal cavities. Both the cavity size and the electronic property of the acquired macrocycles were fine‐tuned by the nature of the bridging element X. 相似文献
19.
Conghui Tang Mikiko Okumura Hejun Deng David Sarlah 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):15909-15913
A palladium‐catalyzed dearomative syn‐1,4‐oxyamination protocol using non‐activated arenes has been developed. This one‐pot procedure utilizes arenophile chemistry, and the corresponding para‐cycloadducts are treated with oxygen nucleophiles via formal allylic substitution, providing direct access to syn‐1,4‐oxyaminated products. The reaction conditions permit a range of arenes, as well as different O‐nucleophiles, such as oximes and benzyl alcohols. Moreover, this process was established in an asymmetric fashion, delivering products with high enantioselectivity. The dearomatized products are amenable to a multitude of further derivatizations ranging from olefin chemistry to C?H activation, giving rise to a diverse set of new functionalities. Overall, this dearomative functionalization offers rapid and controlled formation of molecular complexity, enabling straightforward access to functionalized small molecules from simple and readily available arenes. 相似文献
20.
Pd‐Catalyzed C−H Alkylation of Arenes Using PyrDipSi,a Transformable and Removable Silicon‐Tethered Directing Group 下载免费PDF全文
Dhruba Sarkar Prof. Dr. Vladimir Gevorgyan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(32):11201-11204
An efficient Pd‐catalyzed ortho‐C?H alkylation reaction of arenes using a transformable and removable Si‐tethered pyridyldiisopropylsilyl (PyrDipSi) directing group has been developed. In addition, the PyrDipSi directing group allows for an efficient sequential double‐fold C?H alkylation/oxygenation of arenes to produce meta‐alkylated phenols. This directing group can easily be removed or converted into valuable functionalities, such as aryl, iodo, boronic ester, or phenol. 相似文献