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1.
A mild, efficient, and solvent‐free version of Friedländer annulation of 2‐amino ketones and α‐methylene carbonyl compounds for the synthesis of polysubstituted quinolines using a catalytic amount of commercially available iron(III) chloride at room temperature in excellent yields is described. 相似文献
2.
Danqing Zheng Armido Studer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(44):15950-15954
An enantioselective three‐component radical reaction of quinolines or pyridines with enamides and α‐bromo carbonyl compounds by dual photoredox and chiral Brønsted acid catalysis is presented. A range of valuable chiral γ‐amino‐acid derivatives are accessible in high chemo‐, regio‐, and enantioselectivity from simple, readily available starting materials under mild reaction conditions. Using the same strategy, the asymmetric synthesis of 1,2‐diamine derivatives is also reported. 相似文献
3.
Efficient ruthenium‐, rhodium‐, palladium‐, copper‐ and iridium‐catalysed methodologies have been recently developed for the synthesis of quinolines by the reaction of 2‐aminobenzyl alcohols with carbonyl compounds (aldehydes and ketones) or the related alcohols. The reaction is assumed to proceed via a sequence involving initial metal‐catalysed oxidation of 2‐aminobenzyl alcohols to the related 2‐aminobenzaldehydes, followed by cross aldol reaction with a carbonyl compound under basic conditions to afford α,β‐unsaturated carbonyl compounds. These aldehydes or ketones can be also generated in situ via dehydrogenation of the related primary and secondary alcohols. In the final step cyclodehydration of the α,β‐unsaturated carbonyl compound intermediates gives quinolines. Good yields of quinolines were also obtained by reacting 2‐nitrobenzyl alcohols and secondary alcohols in the presence of a ruthenium catalyst. Finally, aniline derivatives afforded also a useful access to quinolines by the reaction with 1,3‐propanediol or 3‐amino‐1‐propanol, or in a three‐component reaction with benzyl alcohol and aliphatic alcohols. 相似文献
4.
Esmat Tavakolinejad Kermani Hojatollah Khabazzadeh Tayebeh Jazinizadeh 《Journal of heterocyclic chemistry》2011,48(5):1192-1196
A rapid and an efficient method for the preparation of a variety of substituted quinolines has been developed through the reactions of o‐aminoarylketones with carbonyl compounds containing a reactive α‐methylene moiety in the presence of molten [Et3NH][HSO4] under solvent‐free conditions in high yields. J. Heterocyclic Chem., (2011). 相似文献
5.
The efficient, regioselective synthesis of functionalized/annulated quinolines was achieved by the coupling of 2‐aminoaryl ketones with alkynes/active methylenes/α‐oxoketene dithioacetals promoted by InCl3 in refluxing acetonitrile as well as under solvent‐free conditions in excellent yields. This transformation presumably proceeded through the hydroamination–hydroarylation of alkynes, and the Friedländer annulation of active methylene compounds and α‐oxoketene dithioacetals with 2‐aminoarylketones. In addition, simple reductive and oxidative cyclization of 2‐nitrobenzaldehyde and 2‐aminobenzylalcohol, respectively, afforded substituted quinolines. Systematic optimization of the reaction parameters allowed us to identify two‐component coupling (2CC) conditions that were tolerant of a wide range of functional groups, thereby providing densely functionalized/annulated quinolines. This approach tolerates the synthesis of various bioactive quinoline frameworks from the same 2‐aminoarylketones under mild conditions, thus making this strategy highly useful in diversity‐oriented synthesis (DOS). The scope and limitations of the alkyne‐, activated methylene‐, and α‐oxoketene dithioacetal components on the reaction were also investigated. 相似文献
6.
Hongyang Zhao Yanpeng Xing Prof. Dr. Ping Lu Prof. Dr. Yanguang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(42):15144-15150
Cyclopenta[b]quinolines and cyclohexa[b]quinolines were prepared via the reactions of α‐diazo ketones with N‐(2‐cyclopropylidenemethylphenyl)phosphanimines and N‐(2‐cyclobutylidenemethylphenyl) phosphanimine, respectively. The reaction proceeds in a cascade involving ketenimine formation, 6 π‐electron ring closure, and 1,3‐alkyl shift. A similar approach was developed for the synthesis of dihydropyrrolo‐[2,3‐b]quinolines from N‐(2‐cyclopropylidenemethylphenyl)phosphanimines and isocyanates. 相似文献
7.
Kazuaki Ishihara Kazuki Nishimura Katsuya Yamakawa 《Angewandte Chemie (International ed. in English)》2020,59(40):17641-17647
Catalytic enantioselective α‐fluorination reactions of carbonyl compounds are among the most powerful and efficient synthetic methods for constructing optically active α‐fluorinated carbonyl compounds. Nevertheless, α‐fluorination of α‐nonbranched carboxylic acid derivatives is still a big challenge because of relatively high pKa values of their α‐hydrogen atoms and difficulty of subsequent synthetic transformation without epimerization. Herein we show that chiral copper(II) complexes of 3‐(2‐naphthyl)‐l ‐alanine‐derived amides are highly effective catalysts for the enantio‐ and site‐selective α‐fluorination of N‐(α‐arylacetyl) and N‐(α‐alkylacetyl) 3,5‐dimethylpyrazoles. The substrate scope of the transformation is very broad (25 examples including a quaternary α‐fluorinated α‐amino acid derivative). α‐Fluorinated products were converted into the corresponding esters, secondary amides, tertiary amides, ketones, and alcohols with almost no epimerization in high yield. 相似文献
8.
Photochemical Carbopyridylation of Alkenes Using N‐Alkenoxypyridinium Salts as Bifunctional Reagents
Gangadhar Rao Mathi Yujin Jeong Yonghoon Moon Sungwoo Hong 《Angewandte Chemie (International ed. in English)》2020,59(5):2049-2054
N‐Alkenoxypyridinium salts have been used as synthons for the umpolung reaction of enolates for the preparation of α‐functionalized carbonyl compounds. In contrast, we found that the photoreduction of N‐alkenoxypyridinium salts generates α‐carbonyl radicals after cleavage of the N?O bond, thereby allowing simultaneous incorporation of α‐keto and pyridyl groups across unactivated alkenes. In the process, the formed α‐carbonyl radicals engage unactivated alkenes to afford alkyl radical intermediates poised for subsequent addition to pyridinium salts, which ultimately affords a variety of γ‐pyridyl ketones under mild reaction conditions. This transformation is characterized by a broad substrate scope and good functional‐group compatibility, and the utility of this transformation was further demonstrated by the late‐stage functionalization of complex biorelevant molecules. 相似文献
9.
《中国化学会会志》2018,65(7):888-892
A facile and efficient approach toward the synthesis of functionalized quinolines and 1,2‐dihydroquinolines from carbonyl compounds and 2‐vinylanilines is described. The protocol utilizes the nonhazardous and less expensive FeCl3 as catalyst with wide functional group tolerance and avoiding heavy metal impurities in the products. 相似文献
10.
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
11.
Tandem Pd/Au‐Catalyzed Route to α‐Sulfenylated Carbonyl Compounds from Terminal Propargylic Alcohols and Thiols 下载免费PDF全文
Dr. Srijit Biswas Rahul A. Watile Prof. Dr. Joseph S. M. Samec 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2159-2163
An efficient and highly atom‐economical tandem Pd/Au‐catalyzed route to α‐sulfenylated carbonyl compounds from terminal propargylic alcohols and thiols has been developed. This one‐step procedure has a wide substrate scope with respect to substituents at the α‐position of the alcohol. Both aromatic and aliphatic thiols generated the α‐sulfenylated carbonyl products in good to excellent yields. A mechanism is proposed in which the reaction proceeds through a Pd‐catalyzed regioselective hydrothiolation at the terminal triple bond of the propargyl alcohol followed by an Au‐catalyzed 1,2‐hydride migration. 相似文献
12.
Due to the chemoselective dehalogenation by SmI2, the addition of a-halomethylsulfones to carbonyl compounds afforded ,β-hydroxysulfones. Those reactions with α-bromomethylsulfones gave the products in moderate to good yields. The SmI2-mediated addition of gem-dihalomethylsulfones to ketones also afforded α-halo-β-hydroxysulfones in moderate yields. 相似文献
13.
Palladium‐Catalyzed Oxidative Difunctionalization of Alkenes with α‐Carbonyl Alkyl Bromides Initiated through a Heck‐type Insertion: A Route to Indolin‐2‐ones 下载免费PDF全文
Jian‐Hong Fan Wen‐Ting Wei Ming‐Bo Zhou Dr. Ren‐Jie Song Prof. Dr. Jin‐Heng Li 《Angewandte Chemie (International ed. in English)》2014,53(26):6650-6654
The oxidative interception of various σ‐alkyl palladium(II) intermediates with additional reagents for the difunctionalization of alkenes is an important research area. A new palladium‐catalyzed oxidative difunctionalization reaction of alkenes with α‐carbonyl alkyl bromides is described, in which the σ‐alkyl palladium(II) intermediate is generated through a Heck insertion and trapped using an aryl C(sp2)? H bond. This method can be applied to various α‐carbonyl alkyl bromides, including primary, secondary, and tertiary α‐bromoalkyl esters, ketones, and amides. 相似文献
14.
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
15.
Borane‐Catalyzed Reductive α‐Silylation of Conjugated Esters and Amides Leaving Carbonyl Groups Intact 下载免费PDF全文
Youngchan Kim Prof. Dr. Sukbok Chang 《Angewandte Chemie (International ed. in English)》2016,55(1):218-222
Described herein is the development of the B(C6F5)3‐catalyzed hydrosilylation of α,β‐unsaturated esters and amides to afford synthetically valuable α‐silyl carbonyl products. The α‐silylation occurs chemoselectively, thus leaving the labile carbonyl groups intact. The reaction features a broad scope of both acyclic and cyclic substrates, and the synthetic utility of the obtained α‐silyl carbonyl products is also demonstrated. Mechanistic studies revealed two operative steps: fast 1,4‐hydrosilylation of conjugated carbonyls and then slow silyl group migration of a silyl ether intermediate. 相似文献
16.
An Alternative to the Classical α‐Arylation: The Transfer of an Intact 2‐Iodoaryl from ArI(O2CCF3)2 下载免费PDF全文
Dr. Zhiyu Jia Dr. Erik Gálvez Prof. Dr. Rosa María Sebastián Prof. Dr. Roser Pleixats Dr. Ángel Álvarez‐Larena Dr. Eddy Martin Prof. Dr. Adelina Vallribera Dr. Alexandr Shafir 《Angewandte Chemie (International ed. in English)》2014,53(42):11298-11301
The α‐arylation of carbonyl compounds is generally accomplished under basic conditions, both under metal catalysis and via aryl transfer from the diaryl λ3‐iodanes. Here, we describe an alternative metal‐free α‐arylation using ArI(O2CCF3)2 as the source of a 2‐iodoaryl group. The reaction is applicable to activated ketones, such as α‐cyanoketones, and works with substituted aryliodanes. This formal C? H functionalization reaction is thought to proceed through a [3,3] rearrangement of an iodonium enolate. The final α‐(2‐iodoaryl)ketones are versatile synthetic building blocks. 相似文献
17.
A simple and efficient method has been developed for the condensation of o‐aminoaryl ketones with α‐methylene ketones in the presence of catalytic amounts of LiBr to afford the corresponding fused cyclic quinolines in high yield using the Friedlander heteroannulation reaction. The reaction works at ambient temperature to give the products within 1.5–2 h. 相似文献
18.
Enolizable Carbonyls and N,O‐Acetals: A Rational Approach for Room‐Temperature Lewis Superacid‐Catalyzed Direct α‐Amidoalkylation of Ketones and Aldehydes 下载免费PDF全文
Bahria Touati Dr. Abderrahman El Bouakher Dr. Catherine Taillier Dr. Raja Ben Othman Prof. Dr. Malika Trabelsi‐Ayadi Dr. Sylvain Antoniotti Dr. Elisabet Duñach Prof. Dr. Vincent Dalla 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(17):6012-6022
An efficient catalytic room‐temperature direct α‐amidoalkylation of carbonyl donors, that is, ketones and aldehydes with unbiased N,O‐acetals, is described. Sn(NTf2)4 is an optimal catalyst to promote this challenging transformation at low loading and the reaction shows promising scope. A comprehensive and rational evaluation of this reaction has led to the establishment of an empirical scale of nucleophilic reactivity for a broad set of ketones that should be helpful in the synthetic design and development of carbonyl α‐functionalization methods. 相似文献
19.
Hua Cao Prof. Huanfeng Jiang Prof. Gaoqing Yuan Zhengwang Chen Chaorong Qi Huawen Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(34):10553-10559
The formation of carbon–carbon and carbon–oxygen bonds continues to be an active and challenging field of chemical research. Nanoparticle catalysis has attracted considerable attention owing to its environmentally benign and high activity toward the reactions. Herein, we described a novel and effective nano‐Cu2O‐catalyzed one‐pot domino process for the regioselective synthesis of α‐carbonyl furans. Various electron‐deficient alkynes with 2‐yn‐1‐ols underwent this process smoothly in moderate to good yields in the presence of air at atmospheric pressure. It is especially noteworthy that a novel 2,4,5‐trisubstituted 3‐ynylfuran was formed in an extremely direct manner without tedious stepwise synthesis. Additionally, as all of the starting materials are readily available, this method may allow the synthesis of more complex α‐carbonyl furans. An experiment to elucidate the mechanism suggested that the process involved a carbene intermediate. 相似文献
20.
Dr. Ryo Murakami Kentaro Sano Dr. Tomohiro Iwai Prof. Dr. Tohru Taniguchi Prof. Dr. Kenji Monde Prof. Dr. Masaya Sawamura 《Angewandte Chemie (International ed. in English)》2018,57(30):9465-9469
The palladium‐catalyzed asymmetric side‐chain C(α)‐allylation of 2‐alkylpyridines, without using an external base, was developed. The high linear selectivities and enantioselectivities were achieved using new chiral diamidophosphite monodentate ligands. Given that the reaction conditions do not require an external base, this catalyst system enabled chemoselective C(α)‐allylation of 2‐alkylpyridines containing α‐carbonyl C?H bonds, which are more acidic than α‐pyridyl C?H bonds. 相似文献