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1.
Shang‐Zheng Sun Prof. Ruben Martin 《Angewandte Chemie (International ed. in English)》2018,57(14):3622-3625
A nickel‐catalyzed reductive arylation of ambiphilic α‐bromoalkyl boronic esters with aryl halides is described. This platform provides an unrecognized opportunity to promote the catalytic umpolung reactivity of ambiphilic reagents with aryl halides, thus unlocking a new cross‐coupling strategy that complements existing methods for the preparation of densely functionalized alkyl‐substituted organometallic reagents from simple and readily accessible precursors. 相似文献
2.
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
3.
Haixing Guan Qianwen Zhang Prof. Dr. Patrick J. Walsh Prof. Dr. Jianyou Mao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(13):5210-5215
A unique nickel/organic photoredox co-catalyzed asymmetric reductive cross-coupling between α-chloro esters and aryl iodides is developed. This cross-electrophile coupling reaction employs an organic reductant (Hantzsch ester), whereas most reductive cross-coupling reactions use stoichiometric metals. A diverse array of valuable α-aryl esters is formed under these conditions with high enantioselectivities (up to 94 %) and good yields (up to 88 %). α-Aryl esters represent an important family of nonsteroidal anti-inflammatory drugs. This novel synergistic strategy expands the scope of Ni-catalyzed reductive asymmetric cross-coupling reactions. 相似文献
4.
Design of New Ligands for the Palladium‐Catalyzed Arylation of α‐Branched Secondary Amines 下载免费PDF全文
Nathaniel H. Park Ekaterina V. Vinogradova Dr. David S. Surry Prof. Dr. Stephen L. Buchwald 《Angewandte Chemie (International ed. in English)》2015,54(28):8259-8262
In Pd‐catalyzed C? N cross‐coupling reactions, α‐branched secondary amines are difficult coupling partners and the desired products are often produced in low yields. In order to provide a robust method for accessing N‐aryl α‐branched tertiary amines, new catalysts have been designed to suppress undesired side reactions often encountered when these amine nucleophiles are used. These advances enabled the arylation of a wide array of sterically encumbered amines, highlighting the importance of rational ligand design in facilitating challenging Pd‐catalyzed cross‐coupling reactions. 相似文献
5.
Ligand‐free Pd/Cu‐catalyzed decarboxylative coupling of aryl iodides with α‐oxocarboxylates 下载免费PDF全文
This paper describes a palladium/copper‐catalyzed decarboxylative coupling of aryl iodides with α‐oxocarboxylates. The cross‐coupling reaction gives high chemical yields of aryl ketones and has wide functional group tolerance, making the transformation an attractive alternative to the traditional cross‐coupling approaches for aryl ketones. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
6.
Benito Alcaide Prof. Dr. Pedro Almendros Dr. Teresa Martínez del Campo Rocío Carrascosa 《化学:亚洲杂志》2008,3(7):1140-1145
A mild, palladium(II)‐catalyzed reaction of α‐allenols with α‐allenic esters in a heterocyclization/cross‐coupling sequence, applicable to a wide range of substitution patterns, has been developed for the preparation of 2,3,4‐trifunctionalized 2,5‐dihydrofurans. Our studies indicate high levels of chemo‐ and regiocontrol. The possibility of using optically active substrates as well as substrates of increased steric demand, such as tertiary α‐allenols, makes this novel sequence of heterocyclization/cross‐coupling an attractive method in organic synthesis. The current mechanistic hypothesis invokes a regiocontrolled palladium(II)‐mediated intramolecular oxypalladation of the free allenol component, that then undergoes a cross‐coupling reaction with the allenic ester partner, followed by a trans‐β‐deacyloxypalladation with concomitant regeneration of the PdII species. 相似文献
7.
Nickel‐Catalyzed Reductive Cross‐Coupling of Aryl Halides with Monofluoroalkyl Halides for Late‐Stage Monofluoroalkylation 下载免费PDF全文
Hao‐Ran Zhang Kai‐Fan Zhang Yi‐Ning Wang Prof. Dr. Xi‐Sheng Wang 《Angewandte Chemie (International ed. in English)》2018,57(26):7634-7639
A combinatorial nickel‐catalyzed monofluoroalkylation of aryl halides with unactivated fluoroalkyl halides by reductive cross‐coupling has been developed. This method demonstrated high efficiency, mild conditions, and excellent functional‐group tolerance, thus enabling the late‐stage monofluoroalkylation of diverse drugs. The key to success was the combination of diverse readily available bidentate and monodentate pyridine‐type nitrogen ligands with nickel, which in situ generated a variety of readily tunable catalysts to promote fluoroalkylation with broad scope with respect to both coupling partners. This combinatorial catalysis strategy offers a solution for nickel‐catalyzed reductive cross‐coupling reactions and provides an efficient way to synthesize fluoroalkylated druglike molecules for drug discovery. 相似文献
8.
Enantioselective Palladium‐Catalyzed Insertion of α‐Aryl‐α‐diazoacetates into the OH Bonds of Phenols 下载免费PDF全文
Xiu‐Lan Xie Prof. Shou‐Fei Zhu Jun‐Xia Guo Yan Cai Prof. Qi‐Lin Zhou 《Angewandte Chemie (International ed. in English)》2014,53(11):2978-2981
A palladium‐catalyzed asymmetric O? H insertion reaction was developed. Palladium complexes with chiral spiro bisoxazoline ligands promoted the insertion of α‐aryl‐α‐diazoacetates into the O? H bond of phenols with high yield and excellent enantioselectivity under mild reaction conditions. This palladium‐catalyzed asymmetric O? H insertion reaction provided an efficient and highly enantioselective method for the preparation of synthetically useful optically active α‐aryl‐α‐aryloxyacetates. 相似文献
9.
《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
10.
Expedient Synthesis of Chiral α‐Amino Acids through Nickel‐Catalyzed Reductive Cross‐Coupling 下载免费PDF全文
Xi Lu Jun Yi Zhen‐Qi Zhang Jian‐Jun Dai Jing‐Hui Liu Prof. Bin Xiao Prof. Yao Fu Prof. Lei Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15339-15343
A novel method for the synthesis of non‐natural L ‐ and D ‐amino acids by a Ni‐catalyzed reductive cross‐coupling reaction is described. This strategy enables the racemization‐free cross‐coupling of serine/homoserine‐ derived iodides with aryl/acyl/alkyl halides. It provides convenient access to varieties of enantiopure and functionalized amino acids, which are important building blocks in bioactive compounds and pharmaceuticals. 相似文献
11.
Juri Skotnitzki Alexander Kremsmair Daniel Keefer Ye Gong Regina de Vivie‐Riedle Paul Knochel 《Angewandte Chemie (International ed. in English)》2020,59(1):320-324
We report palladium‐catalyzed cross‐coupling reactions of chiral secondary non‐stabilized dialkylzinc reagents, prepared from readily available chiral secondary alkyl iodides, with alkenyl and aryl halides. This method provides α‐chiral alkenes and arenes with very high retention of configuration (dr up to 98:2) and satisfactory overall yields (up to 76 % for 3 reaction steps). The configurational stability of these chiral non‐stabilized dialkylzinc reagents was determined and exceeded several hours at 25 °C. DFT calculations were performed to rationalize the stereoretention during the catalytic cycle. Furthermore, the cross‐coupling reaction was applied in an efficient total synthesis of the sesquiterpenes (S)‐ and (R)‐curcumene with control of the absolute stereochemistry. 相似文献
12.
Jin‐Miao Tian Ai‐Fang Wang Ju‐Song Yang Xiao‐Jing Zhao Yong‐Qiang Tu Shu‐Yu Zhang Zhi‐Min Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11139-11143
A novel chiral 1,5‐N,N‐bidentate ligand based on a spirocyclic pyrrolidine oxazoline backbone was designed and prepared, and it coordinates CuBr in situ to form an unprecedented catalyst that enables efficient oxidative cross‐coupling of 2‐naphthols. Air serves as an external oxidant and generates a series of C1‐symmetric chiral BINOL derivatives with high enantioselectivity (up to 99 % ee) and good yield (up to 87 %). This approach is tolerant of a broader substrates scope, particularly substrates bearing various 3‐ and 3′‐substituents. A preliminary investigation using one of the obtained C1‐symmetric BINOL products was used as an organocatalyst, exhibiting better enantioselectivity than the previously reported organocatalyst, for the asymmetric α‐alkylation of amino esters. 相似文献
13.
Birgit Prüger Dr. Gretchen E. Hofmeister Prof. Dr. Christian Borch Jacobsen David G. Alberg Prof. Dr. Martin Nielsen Dr. Karl Anker Jørgensen Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(12):3783-3790
Transition‐metal‐free formal Sonogashira coupling and α‐carbonyl arylation reactions have been developed. These transformations are based on the nucleophilic aromatic substitution (SNAr) of β‐carbonyl sulfones to electron‐deficient aryl fluorides, producing a key intermediate that, depending on the reaction conditions, gives the aromatic alkynes or α‐aryl carbonyl compounds. The development of these reactions is presented and, based on investigations under basic and acidic conditions, mechanisms have been proposed. To develop the formal Sonogashira coupling further, a milder, two‐step protocol is also disclosed that expands the reaction concept. The scope of these reactions is demonstrated for the synthesis of Sonogashira and α‐carbonyl arylated products from a range of electron‐deficient aryl fluorides with a variety of functional groups and aryl‐, heteroaryl‐, alkyl‐, and alkoxy‐substituted sulfone nucleophiles. These transition‐metal‐free reactions complement the metal‐catalyzed versions in terms of substitution patterns, simplicity, and reaction conditions. 相似文献
14.
2,4‐Dinitrophenol‐Catalyzed α‐C(sp3)−H and C(sp)−H Bond Functionalization of Cyclic Amines and Alkynes: Highly Regio‐/Diastereoselective Synthesis of α‐Alkynyl‐3‐Amino‐2‐Oxindoles 下载免费PDF全文
Dr. Mukesh Kumar Banni P. Kaur Prof. Swapandeep S Chimni 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(29):9948-9952
A transition‐metal‐ and oxidant‐free DNP (2,4‐dinitrophenol)‐catalyzed atom‐economical regio‐ and diastereoselective synthesis of monofunctionalized α‐alkynyl‐3‐amino‐2‐oxindole derivatives by C?H bond functionalization of cyclic amines and alkynes with indoline‐2,3‐diones has been developed. This cascade event sequentially involves the reductive amination of indoline‐2,3‐dione by imine formation and cross coupling between C(sp3)?H and C(sp)?H of the cyclic amines and alkynes. This reaction offers an efficient and attractive pathway to different types of α‐alkynyl‐3‐amino‐2‐oxindole derivatives in good yields with a wide tolerance of functional groups. The salient feature of this methodology is that it completely suppresses the homocoupling of alkynes. To the best of our knowledge, this is the first example of a DNP‐catalyzed metal‐free direct C(sp3)?H and C(sp)?H bond functionalization providing biologically active α‐alkynyl‐3‐amino‐2‐oxindole scaffolds. 相似文献
15.
Highly Enantioselective Formation of α‐Allyl‐α‐Arylcyclopentanones via Pd‐Catalysed Decarboxylative Asymmetric Allylic Alkylation 下载免费PDF全文
Dr. Ramulu Akula Dr. Robert Doran Prof. Patrick J. Guiry 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(29):9938-9942
A highly enantioselective Pd‐catalysed decarboxylative asymmetric allylic alkylation of cyclopentanone derived α‐aryl‐β‐keto esters employing the (R,R)‐ANDEN‐phenyl Trost ligand has been developed. The product (S)‐α‐allyl‐α‐arylcyclopentanones were obtained in excellent yields and enantioselectivities (up to >99.9 % ee). This represents one of the most highly enantioselective formations of an all‐carbon quaternary stereogenic center reported to date. This reaction was demonstrated on a 4.0 mmol scale without any deterioration of enantioselectivity and was exploited as the key enantioselective transformation in an asymmetric formal synthesis of the natural product (+)‐tanikolide. 相似文献
16.
Intra‐ and Intermolecular Nickel‐Catalyzed Reductive Cross‐Electrophile Coupling Reactions of Benzylic Esters with Aryl Halides 下载免费PDF全文
Mikhail O. Konev Luke E. Hanna Prof. Dr. Elizabeth R. Jarvo 《Angewandte Chemie (International ed. in English)》2016,55(23):6730-6733
Nickel‐catalyzed cross‐electrophile coupling reactions of benzylic esters and aryl halides have been developed. Both inter‐ and intramolecular variants proceed under mild reaction conditions. A range of heterocycles and functional groups are tolerated under the reaction conditions. Additionally, the first example of a stereospecific cross‐electrophile coupling of a secondary benzylic ester is described. 相似文献
17.
Tiffany Q. Chen David W. C. MacMillan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14726-14730
Here, we demonstrate that a metallaphotoredox‐catalyzed cross‐electrophile coupling mechanism provides a unified method for the α‐arylation of diverse activated alkyl chlorides, including α‐chloroketones, α‐chloroesters, α‐chloroamides, α‐chlorocarboxylic acids, and benzylic chlorides. This strategy, which is effective for a wide variety of aryl bromide coupling partners, is predicated upon a halogen atom abstraction/nickel radical‐capture mechanism that is generically successful across an extensive range of carbonyl substrates. The construction and use of arylacetic acid products have further enabled two‐step protocols for the delivery of valuable building blocks for medicinal chemistry, such as aryldifluoromethyl and diarylmethane motifs. 相似文献
18.
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
19.
Yasumasa Hamada 《Chemical record (New York, N.Y.)》2014,14(2):235-250
This review describes our recent works on the diastereo‐ and enantioselective synthesis of anti‐β‐hydroxy‐α‐amino acid esters using transition‐metal–chiral‐bisphosphine catalysts. A variety of transition metals, namely ruthenium (Ru), rhodium (Rh),iridium (Ir), and nickel (Ni), in combination with chiral bisphosphines, worked well as catalysts for the direct anti‐selective asymmetric hydrogenation of α‐amino‐β‐keto ester hydrochlorides, yielding anti‐β‐hydroxy‐α‐amino acid esters via dynamic kinetic resolution (DKR) in excellent yields and diastereo‐ and enantioselectivities. The Ru‐catalyzed asymmetric hydrogenation of α‐amino‐β‐ketoesters via DKR is the first example of generating anti‐β‐hydroxy‐α‐amino acids. Complexes of iridium and axially chiral bisphosphines catalyze an efficient asymmetric hydrogenation of α‐amino‐β‐keto ester hydrochlorides via dynamic kinetic resolution. A homogeneous Ni–chiral‐bisphosphine complex also catalyzes an efficient asymmetric hydrogenation of α‐amino‐β‐keto ester hydrochlorides in an anti‐selective manner. As a related process, the asymmetric hydrogenation of the configurationally stable substituted α‐aminoketones using a Ni catalyst via DKR is also described. 相似文献
20.
Barry M. Trost Johnathan E. Schultz Yu Bai 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):11946-11951
We describe the development of a Pd‐catalyzed decarboxylative asymmetric allylic alkylation of α‐nitro allyl esters to afford acyclic tetrasubstituted nitroalkanes. Optimization of the reaction parameters revealed unique ligand and solvent combinations crucial for achieving chemo‐ and enantioselective C‐alkylation of electronically challenging benzylic nitronates and sterically encumbered 2‐allyl esters. Substrates were efficiently accessed in a combinatorial fashion by a cross‐Claisen/ α‐arylation sequence. The method provides functional group orthogonality that complements nucleophilic imine allylation strategies for α‐tertiary amine synthesis. 相似文献