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1.
《Angewandte Chemie (International ed. in English)》2017,56(41):12774-12777
We report a general preparation of arylated bicyclo[1.1.1]pentanes through the opening of [1.1.1]propellane with various arylmagnesium halides. After transmetalation with ZnCl2 and Negishi cross‐coupling with aryl and heteroaryl halides, bis‐arylated bicyclo[1.1.1]pentanes are obtained. These bis‐arylated bicyclo[1.1.1]pentanes may be considered as bioisosteres of internal alkynes. Bioisosteres of tazarotene and the metabotropic glutamate receptor 5 (mGluR5) antagonist 2‐methyl‐6‐(phenylethynyl)pyridine were prepared and their physicochemical properties were evaluated. 相似文献
2.
Anthony Millet David Dailler Dr. Paolo Larini Prof. Dr. Olivier Baudoin 《Angewandte Chemie (International ed. in English)》2014,53(10):2678-2682
The palladium‐catalyzed ligand‐controlled arylation of α‐zincated acyclic amines, obtained by directed α‐lithiation and transmetalation, is described. Whereas PtBu3 gave rise to α‐arylated Boc‐protected amines, more flexible N‐phenylazole‐based phosphine ligands induced major β‐arylation through migrative cross‐coupling. 相似文献
3.
Venkata Ashok Kothapalli Manasa Shetty Christopher de los Santos Christopher E. Hobbs 《Journal of polymer science. Part A, Polymer chemistry》2016,54(1):179-185
The use of a thio‐bromo click strategy as an efficient postpolymerization tool is described. Norbornene derivatives bearing an α‐bromo ester could be polymerized using Grubbs 2nd generation initiator to provide α‐bromo ester‐containing homo‐and block copolymers that could be efficiently functionalized through reactions with various thiols. A one‐pot strategy was also used, in which up to four different thiols were reacted simultaneously. This chemistry could also be used as an efficient cross‐linking strategy to form ROMP‐based gels as well as a tool for terminal functionalization of polypropylene‐based oligomers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 179–185 相似文献
4.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(4):1102-1106
We report a robust and broadly applicable CoCl2‐catalyzed cross‐coupling between functionalized aryl and heteroaryl zinc pivalates and various electron‐poor aryl and heteroaryl halides (X=Cl, Br, I). Couplings with (E)‐ or (Z)‐bromo‐ or iodo‐alkenes proceed with retention of configuration. Also, alkynyl bromides react with arylzinc pivalates providing arylated alkynes. 相似文献
5.
Bowen Li Tiejun Li Muinat A. Aliyu Zhen Hua Li Wenjun Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(33):11477-11481
We herein report an enantioselective palladium‐catalyzed cross‐coupling between α‐bromo carboxamides and aryl boronic acids, generating a series of chiral α‐aryl carboxamides in good yields and excellent enantioselectivities. The development of a chiral P,P=O ligand was critical in overcoming the second transmetalation issue and allows the first asymmetric palladium‐catalyzed coupling of α‐bromo carbonyl compounds. 相似文献
6.
Venkateshwarlu Gurram Dr. Narender Pottabathini Ramesh Garlapati Dr. Avinash B. Chaudhary Dr. Balaram Patro Prof. Mahesh K. Lakshman 《化学:亚洲杂志》2012,7(8):1853-1861
Reaction conditions for the C? C cross‐coupling of O6‐alkyl‐2‐bromo‐ and 2‐chloroinosine derivatives with aryl‐, hetaryl‐, and alkylboronic acids were studied. Optimization experiments with silyl‐protected 2‐bromo‐O6‐methylinosine led to the identification of [PdCl2(dcpf)]/K3PO4 in 1,4‐dioxane as the best conditions for these reactions (dcpf=1,1′‐bis(dicyclohexylphosphino)ferrocene). Attempted O6‐demethylation, as well as the replacement of the C‐6 methoxy group by amines, was unsuccessful, which led to the consideration of Pd‐cleavable groups such that C? C cross‐coupling and O6‐deprotection could be accomplished in a single step. Thus, inosine 2‐chloro‐O6‐allylinosine was chosen as the substrate and, after re‐evaluation of the cross‐coupling conditions with 2‐chloro‐O6‐methylinosine as a model substrate, one‐step C? C cross‐coupling/deprotection reactions were performed with the O6‐allyl analogue. These reactions are the first such examples of a one‐pot procedure for the modification and deprotection of purine nucleosides under C? C cross‐coupling conditions. 相似文献
7.
Marija H. Habicht Friedrich Wossidlo Manuela Weber Prof. Dr. Christian Müller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12877-12883
The facile access to 3‐bromo‐2‐pyrone allows the preparation of 6‐bromo‐2‐trimethylsilyl‐phosphinine by a [4+2] cycloaddition with Me3Si‐C≡P for the first time. The regioselectivity of this reaction could be verified by means of single crystal X‐ray diffraction of the corresponding W0 complex. In the presence of ZnBr2 and dppp (1,3‐bis(diphenylphosphino)propane) as a bidentate ligand, the bromo‐phosphinine quantitatively undergoes a Negishi cross‐coupling reaction with PhLi that selectively leads to 6‐phenyl‐2‐trimethylsilyl‐phosphinine. This heterocycle could again be characterized by means of X‐ray diffraction as a W0 complex. These results describe a new and convenient route to 2,6‐disubstituted phosphinines that makes use of readily available starting materials. 相似文献
8.
Direct Access to α,α‐Difluoroacylated Arenes by Palladium‐Catalyzed Carbonylation of (Hetero)Aryl Boronic Acid Derivatives
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Thomas L. Andersen Mette W. Frederiksen Katrine Domino Prof. Dr. Troels Skrydstrup 《Angewandte Chemie (International ed. in English)》2016,55(35):10396-10400
A palladium‐catalyzed carbonylative coupling of (hetero)aryl boronates or boronic acid salts with carbon monoxide and α‐bromo‐α,α‐difluoroamides and bromo‐α,α‐difluoroesters is described herein. The method is useful for the synthesis of a diverse selection of (hetero)aryl α,α‐difluoro‐β‐ketoamides and α,α‐difluoro‐β‐ketoesters, which are useful building blocks for the generation of functionalized difluoroacylated and difluoroalkyl arenes. The method could be further extended to a one‐pot protocol for the formation of difluoroacetophenones. 相似文献
9.
Yushin Shibuya Naoki Nakagawa Naoki Miyagawa Toyoko Suzuki Kentaro Okano Atsunori Mori 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(28):9647-9650
The unprecedented synthesis of regioregular head‐to‐tail‐type poly(1,4‐arylene)s bearing different substituents at the 2‐ and 5‐positions is described. They were prepared by the polymerization of 2,5‐disubstituted bromo(chloro)arylenes by selective halogen–metal exchange with a Grignard reagent and subsequent cross‐coupling polymerization with a nickel catalyst [NiCl2(dppp)]. Formation of the regioregular poly(1,4‐arylene)s were confirmed by NMR spectroscopy, and showed remarkable differences to those polymers having uncontrolled regioregularity. Polymerization of bromo(chloro)arylenes with a chiral alkoxy substituent also led to the regioregular head‐to‐tail‐type polyarylene, which demonstrated circular dichroism, thus suggesting formation of a structure with higher‐order regularity. 相似文献
10.
Continuous‐Flow Synthesis of Biaryls by Negishi Cross‐Coupling of Fluoro‐ and Trifluoromethyl‐Substituted (Hetero)arenes
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Dr. Stefan Roesner Prof. Dr. Stephen L. Buchwald 《Angewandte Chemie (International ed. in English)》2016,55(35):10463-10467
A continuous‐flow method for the regioselective arylation of fluoroarenes and fluoropyridines has been developed. The telescoped procedure reported here consists of a three‐step metalation, zincation, and Negishi cross‐coupling sequence, providing efficient access to a variety of functionalized 2‐fluorobiaryl products. Precise temperature control of the metalation step, made possible by continuous‐flow technology, allowed for the efficient preparation of the arylated products in high yields and short residence times. Additionally, several examples of the regioselective arylation of benzotrifluoride derivatives are also provided. 相似文献
11.
Congyu Li Jing‐Mei Yuan Wenqiang Chen Yimiao He Jun Huang Yanmin Huang Qi Xiao Jiarong Sheng Chusheng Huang 《化学:亚洲杂志》2019,14(15):2584-2587
Defluorinative C(sp3)?P bond formation of α‐trifluoromethyl alkenes with phosphine oxides or phosphonates have been achieved under catalyst‐ and oxidant‐free conditions, giving phosphorylation gem‐difluoroalkenes as products. α‐Trifluoromethyl alkenes bearing various of aryl substituents such as halogen, cyano, ester and heterocyclic groups are available in this transformation. The results of control experiments demonstrated that the mechanism of dehydrogenative/defluorinative cross‐coupling reactions was not a radical route, but might be an SN2′ process involving phosphine oxide anion. 相似文献
12.
Gregg M. Schwarzwalder Carson D. Matier Gregory C. Fu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3609-3612
Metal‐catalyzed enantioconvergent cross‐coupling reactions of alkyl electrophiles are emerging as a powerful tool in asymmetric synthesis. To date, high enantioselectivity has been limited to couplings of electrophiles that bear a directing group or a proximal p/π orbital. Herein, we demonstrate for the first time that enantioconvergent cross‐couplings can be achieved with electrophiles that lack such features; specifically, we establish that a chiral nickel catalyst can accomplish Negishi reactions of racemic α‐halosilanes with alkylzinc reagents with good enantioselectivity under simple and mild conditions, thereby providing access to enantioenriched organosilanes, an important class of target molecules. 相似文献
13.
Masaki Shimizu Prof. Dr. Takuya Kurahashi Dr. Katsuhiro Shimono Dr. Kei Tanaka Ikuhiro Nagao Shin‐ichi Kiyomoto Tamejiro Hiyama Prof. Dr. 《化学:亚洲杂志》2007,2(11):1400-1408
Treatment of 1,1‐bis(pinacolatoboryl)ethene with an excess of 1‐bromo‐1‐lithioethene gave 2,3‐bis(pinacolatoboryl)‐1,3‐butadiene in high yield. Palladium‐catalyzed cross‐coupling of the resulting diborylbutadiene with aryl iodides took place smoothly in the presence of a catalytic amount of Pd(OAc)2/PPh3 and aqueous KOH to give 2,3‐diaryl‐1,3‐butadienes in good yields. The coupling reaction with commercially available 4‐acetoxyphenylmethyl chloride under the same conditions followed by hydrolysis of the acetyl groups gave anolignan B in a one‐pot manner. A variety of [3]‐ to [6]dendralenes were synthesized by palladium‐catalyzed coupling of the diene or 1,1‐bis(pinacolato)borylethene with alkenyl or dienyl halides, respectively, in good yields. 相似文献
14.
Beln Rubial Beatrice S. L. Collins Raphael Bigler Stefan Aichhorn Adam Noble Varinder K. Aggarwal 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(5):1380-1384
The one‐pot sequential coupling of benzylamines, boronic esters, and aryl iodides has been investigated. In the presence of an N‐activator, the boronate complex formed from an ortho‐lithiated benzylamine and a boronic ester undergoes stereospecific 1,2‐metalate rearrangement/anti‐SN2′ elimination to form a dearomatized tertiary boronic ester. Treatment with an aryl iodide under palladium catalysis leads to rearomatizing γ‐selective allylic Suzuki–Miyaura cross‐coupling to generate 1,1‐diarylalkanes. When enantioenriched α‐substituted benzylamines are employed, the corresponding 1,1‐diarylalkanes are formed with high stereospecificity. 相似文献
15.
Efficient Synthesis of Diaryl Ketones by Nickel‐Catalyzed Negishi Cross‐Coupling of Amides by Carbon–Nitrogen Bond Cleavage at Room Temperature Accelerated by a Solvent Effect
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Shicheng Shi Prof. Dr. Michal Szostak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(30):10420-10424
The first Negishi cross‐coupling of amides for the synthesis of versatile diaryl ketones by selective C?N bond activation under exceedingly mild conditions is reported. The cross‐coupling was accomplished with bench‐stable, inexpensive precatalyst [Ni(PPh3)2Cl2] that shows high functional‐group tolerance and enables the synthesis of highly functionalized diaryl ketone motifs. The coupling occurred with excellent chemoselectivity favoring the ketone (cf. biaryl) products. Notably, this process represents the mildest conditions for amide N?C bond activation accomplished to date (room temperature, <10 min). Considering the versatile role of polyfunctional biaryl ketone linchpins in modern organic synthesis, availability, and excellent functional‐group tolerance of organozinc reagents, this strategy provides a new platform for amide N?C bond/organozinc cross‐coupling under mild conditions. 相似文献
16.
tBuLi‐Mediated One‐Pot Direct Highly Selective Cross‐Coupling of Two Distinct Aryl Bromides
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Dr. Carlos Vila Sara Cembellín Dr. Valentín Hornillos Massimo Giannerini Dr. Martín Fañanás‐Mastral Prof. Dr. Ben L. Feringa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15520-15524
A Pd‐catalyzed direct cross‐coupling of two distinct aryl bromides mediated by tBuLi is described. The use of [Pd‐PEPPSI‐IPr] or [Pd‐PEPPSI‐IPent] as catalyst allows for the efficient one‐pot synthesis of unsymmetrical biaryls at room temperature. The key for this selective cross‐coupling is the use of an ortho‐substituted bromide that undergoes lithium–halogen exchange preferentially. 相似文献
17.
Palladium‐Catalyzed Reductive Coupling Reaction of Terminal Alkynes with Aryl Iodides Utilizing Hafnocene Difluoride as a Hafnium Hydride Precursor Leading to trans‐Alkenes
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Herein, we describe a reductive cross‐coupling of alkynes and aryl iodides by using a novel catalytic system composed of a catalytic amount of palladium dichloride and a promoter precursor, hafnocene difluoride (Cp2HfF2, Cp=cyclopentadienyl anion), in the presence of a mild reducing reagent, a hydrosilane, leading to a one‐pot preparation of trans‐alkenes. In this process, a series of coupling reactions efficiently proceeds through the following three steps: (i) an initial formation of hafnocene hydride from hafnocene difluoride and the hydrosilane, (ii) a subsequent hydrohafnation toward alkynes, and (iii) a final transmetalation of the alkenyl hafnium species to a palladium complex. This reductive coupling could be chemoselectively applied to the preparation of trans‐alkenes with various functional groups, such as an alkyl group, a halogen, an ester, a nitro group, a heterocycle, a boronic ester, and an internal alkyne. 相似文献
18.
Lei Zhang Ziqing Zuo Dr. Xuebing Leng Prof. Dr. Zheng Huang 《Angewandte Chemie (International ed. in English)》2014,53(10):2696-2700
An extremely efficient cobalt catalyst for the hydroboration of both vinylarenes and aliphatic α‐olefins with pinacolborane is described, providing the anti‐Markovnikov products with excellent regio‐ and chemoselectivity, broad functional‐group tolerance, and high turnover numbers (up to 19 800). The alkene hydroboration route is further extended to a two‐step, one‐pot hydroboration and cross‐coupling of alkylboronates with aryl chlorides. 相似文献
19.
Shlomy Arava Sourav K. Santra Gulab K. Pathe Raja Kapanaiah Alex M. Szpilman 《Angewandte Chemie (International ed. in English)》2020,59(35):15171-15175
Herein we report on the umpolung of Morita–Baylis–Hillman type intermediates and application to the α‐functionalization of enone C?H bonds. This reaction gives direct access to α‐chloro‐enones, 1,2‐diketones and α‐tosyloxy‐enones. The latter are important intermediates for cross‐coupling reaction and, to the best of our knowledge, cannot be made in a single step from enones in any other way. The proposed mechanism is supported by spectroscopic studies. The key initial step involves conjugate attack of an amine (DABCO or pyridine), likely assisted by hypervalent iodine acting as a Lewis acid leading to formation of an electrophilic β‐ammonium‐enolonium species. Nucleophilic attack by acetate, tosylate, or chloride anion is followed by base induced elimination of the ammonium species to give the noted products. Hydrolysis of α‐acetoxy‐enones lead to formation of 1,2‐diketones. The α‐tosyl‐enones participate in Negishi coupling reactions under standard conditions. 相似文献
20.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(39):12143-12147
A palladium‐catalyzed C(sp3)−C(sp2) Suzuki–Miyaura cross‐coupling of aryl boronic acids and α‐(trifluoromethyl)benzyl tosylates is reported. A readily available, air‐stable palladium catalyst was employed to access a wide range of functionalized 1,1‐diaryl‐2,2,2‐trifluoroethanes. Enantioenriched α‐(trifluoromethyl)benzyl tosylates were found to undergo cross‐coupling to give the corresponding enantioenriched cross‐coupled products with an overall inversion in configuration. The crucial role of the CF3 group in promoting this transformation is demonstrated by comparison with non‐fluorinated derivatives. 相似文献