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1.
Zirconium(IV) chloride catalyzed efficient one-pot synthesis of β-amino/β-acetamido carbonyl compounds at room temperature is described. In the presence of ZrCl4, the three-component Mannich-type reaction via a variety of in situ generated aldimines, with various ketones, aromatic aldehydes and aromatic amines in ethanol, led to the formation of β-amino carbonyl compounds and the four-component Mannich-type reaction of aromatic aldehydes with various ketones, acetonitrile and acetyl chloride resulted in the corresponding β-acetamido carbonyl compounds in high to excellent yields. This methodology has also been applied towards the synthesis of dimeric β-amino/β-acetamido carbonyl compounds. 相似文献
2.
Asymmetric Synthesis of 2,3‐Dihydropyrroles by Ring‐Opening/Cyclization of Cyclopropyl Ketones Using Primary Amines 下载免费PDF全文
Yong Xia Prof. Dr. Xiaohua Liu Haifeng Zheng Dr. Lili Lin Prof. Dr. Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2015,54(1):227-230
The asymmetric ring‐opening/cyclization of cyclopropyl ketones with primary amine nucleophiles was catalyzed by a chiral N,N′‐dioxide/scandium(III) complex through a kinetic resolution process. A broad range of cyclopropyl ketones and primary amines are suitable substrates of this reaction. The corresponding products were afforded in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield) under mild reaction conditions. This method provides a promising access to chiral 2,3‐dihydropyrroles as well as an effective procedure for the kinetic resolution of 2‐substituted cyclopropyl ketones. 相似文献
3.
Asymmetric Ring Opening/Cyclization/Retro‐Mannich Reaction of Cyclopropyl Ketones with Aryl 1,2‐Diamines for the Synthesis of Benzimidazole Derivatives 下载免费PDF全文
Yong Xia Dr. Lili Lin Fenzhen Chang Yuting Liao Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2016,55(40):12228-12232
A highly efficient asymmetric ring‐opening/cyclization/retro‐Mannich reaction of cyclopropyl ketones with aryl 1,2‐diamines has been realized using a chiral N,N′‐dioxide/ScIII catalyst. Benzimidazoles containing chiral side chains were generated under mild reaction conditions in excellent outcomes (up to 99 % yield and 97 % ee). This method also provides efficient access to chiral benzimidazole‐substituted amide and cycloheptene derivatives. 相似文献
4.
Direct Catalytic Asymmetric Mannich Reaction with Dithiomalonates as Excellent Mannich Donors: Organocatalytic Synthesis of (R)‐Sitagliptin 下载免费PDF全文
Dr. Han Yong Bae Mun Jong Kim Jae Hun Sim Prof. Dr. Choong Eui Song 《Angewandte Chemie (International ed. in English)》2016,55(36):10825-10829
In this study, dithiomalonates (DTMs) were demonstrated to be exceptionally efficient Mannich donors in terms of reactivity and stereoselectivity in cinchona‐based‐squaramide‐catalyzed enantioselective Mannich reactions of diverse imines or α‐amidosulfones as imine surrogates. Owing to the superior reactivity of DTMs as compared to conventional malonates, the catalyst loading could be reduced to 0.1 mol % without the erosion of enantioselectivity (up to 99 % ee). Furthermore, by the use of a DTM, even some highly challenging primary alkyl α‐amidosulfones were smoothly converted into the desired adducts with excellent enantioselectivity (up to 97 % ee), whereas the use of a malonate or monothiomalonate resulted in no reaction under identical conditions. The synthetic utility of the chiral Mannich adducts obtained from primary alkyl substrates was highlighted by the organocatalytic, coupling‐reagent‐free synthesis of the antidiabetic drug (?)‐(R)‐sitagliptin. 相似文献
5.
Highly Enantioselective Aza‐Michael Reaction between Alkyl Amines and β‐Trifluoromethyl β‐Aryl Nitroolefins 下载免费PDF全文
Prof. Dr. Yong Huang 《Angewandte Chemie (International ed. in English)》2015,54(51):15414-15418
The aza‐Michael addition reaction is a vital transformation for the synthesis of functionalized chiral amines. Despite intensive research, enantioselective aza‐Michael reactions with alkyl amines as the nitrogen donor have not been successful. We report the use of chiral N‐heterocyclic carbenes (NHCs) as noncovalent organocatalysts to promote a highly selective aza‐Michael reaction between primary alkyl amines and β‐trifluoromethyl β‐aryl nitroolefins. In contrast to classical conjugate‐addition reactions, a strategy of HOMO‐raising activation was used. Chiral trifluoromethylated amines were synthesized in high yield (up to 99 %) with excellent enantioselectivity (up to 98 % ee). 相似文献
6.
Chiral N,N′‐Dioxide‐Organocatalyzed Regio‐, Diastereo‐ and Enantioselective Michael Addition–Alkylation Reaction 下载免费PDF全文
Juhua Feng Xiao Yuan Weiwei Luo Dr. Lili Lin Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15650-15653
A highly regio‐, diastereo‐ and enantioselective Michael addition–alkylation reaction between α‐substituted cyano ketones and (Z)‐bromonitrostyrenes has been realized by using a chiral N,N′‐dioxide as organocatalyst. A variety of substrates performed well in this reaction, and the corresponding multifunctionalized chiral 2,3‐dihydrofurans were obtained in up to 95 % yield with 95:5 dr and 93 % ee. 相似文献
7.
Enantioselective Visible‐Light‐Induced Radical‐Addition Reactions to 3‐Alkylidene Indolin‐2‐ones 下载免费PDF全文
Dr. Dominik Lenhart Dr. Andreas Bauer Dr. Alexander Pöthig Prof. Dr. Thorsten Bach 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6519-6523
The title compounds underwent a facile and high‐yielding addition reaction (19 examples, 66–99 % yield) with various N‐(trimethylsilyl)methyl‐substituted amines upon irradiation with visible light and catalysis by a metal complex. If the alkylidene substituent is non‐symmetric and if the reaction is performed in the presence of a chiral hydrogen‐bonding template, products are obtained with significant enantioselectivity (58–72 % ee) as a mixture of diastereoisomers. Mechanistic studies suggest a closed catalytic cycle for the photoactive metal complex. However, the silyl transfer from the amine occurs not only to the product, but also to the substrate, and interferes with the desired chirality transfer. 相似文献
8.
Zi‐Lei Xia Chao Zheng Xiao‐Wei Liang Yue Cai Shu‐Li You 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1170-1174
By manipulating the reactivity of spiroindolenine species, a sequential Michael/retro‐Mannich/Mannich reaction of ω‐indol‐3‐yl α,β‐unsaturated ketones was developed. In the presence of 10 mol % of a chiral phosphoric acid as the catalyst, a series of 3‐(indol‐3‐yl)‐pyrrolidines were synthesized in high yields (up to 91 %) with excellent stereoselectivities (up to 92 % ee, >19:1 d.r.). The products obtained here undergo diverse functional‐group transformations. The mechanistic proposal of this reaction is supported by DFT calculations. 相似文献
9.
Chiral secondary alcohols with additional functional groups are frequently required as important and valuable synthons for pharmaceuticals, agricultural and other fine chemicals. With the advantages of environmentally benign reaction conditions, broad reaction scope, and high stereoselectivity, biocatalytic reduction of prochiral ketones offers significant potential in the synthesis of optically active alcohols. A CmCR homologous carbonyl reductase from Pichia guilliermondii NRRL Y‐324 was successfully overexpressed. Substrate profile characterization revealed its broad substrate specificity, covering aryl ketones, aliphatic ketones and ketoesters. Furthermore, a variety of ketone substrates were asymmetrically reduced by the purified enzyme with an additionally NADPH regeneration system. The reduction system exhibited excellent enantioselectivity (>99% ee) in the reduction of all the aromatic ketones and ketoesters, except for 2‐bromoacetophenone (93.5% ee). Semi‐preparative reduction of six ketones was achieved with high enantioselectivity (>99% ee) and isolation yields (>80%) within 12 h. This study provides a useful guidance for further application of this enzyme in the asymmetric synthesis of chiral alcohol enantiomers. 相似文献
10.
Barry M. Trost Jacob S. Tracy Tas Yusoontorn Chao‐I Joey Hung 《Angewandte Chemie (International ed. in English)》2020,59(6):2370-2374
The preparation of acyclic β‐fluoro amines bearing tetrasubstituted fluorine stereocenters is described via a direct Zn/ProPhenol‐catalyzed Mannich reaction. The reaction utilizes branched vinyl or alkynyl α‐fluoro ketones that can be coupled with a range of aryl, heteroaryl, vinyl, or cyclopropyl aldimines in high yield and with excellent diastereo‐ (up to >20:1) and enantioselectivity (up to 99 %). The use of readily cleaved tert‐butoxycarbonyl (Boc) or carboxybenzyl (Cbz) imine protecting groups adds utility to the reaction by allowing for easy access to the free amine products under mild and chemoselective reaction conditions. 相似文献
11.
Asymmetric Conjugate Alkynylation of Cyclic α,β‐Unsaturated Carbonyl Compounds with a Chiral Diene Rhodium Catalyst 下载免费PDF全文
Dr. Xiaowei Dou Dr. Yinhua Huang Prof. Dr. Tamio Hayashi 《Angewandte Chemie (International ed. in English)》2016,55(3):1133-1137
Asymmetric conjugate alkynylation of cyclic α,β‐unsaturated carbonyl compounds (ketones, esters, and amides) was realized by use of diphenyl[(triisopropylsilyl)ethynyl]methanol as an alkynylating reagent in the presence of a rhodium catalyst coordinated with a new chiral diene ligand (Fc‐bod; bod=bicyclo[2.2.2]octa‐2,5‐diene, Fc=ferrocenyl) to give high yields of the corresponding β‐alkynyl‐substituted carbonyl compounds with 95–98 % ee. 相似文献
12.
Dr. Xiao‐Qiang Yu Tomohiko Shirai Dr. Yasunori Yamamoto Prof. Dr. Norio Miyaura 《化学:亚洲杂志》2011,6(3):932-937
Rhodium‐catalyzed 1,4‐addition of lithium 5‐methyl‐2‐furyltriolborate ([ArB(OCH2)3CCH3]Li, Ar=5‐methyl‐2‐furyl) to unsaturated ketones to give β‐furyl ketones was followed by ozonolysis of the furyl ring for enantioselective synthesis of γ‐oxo‐carboxylic acids. [Rh(nbd)2]BF4 (nbd=2,5‐norbornadiene) chelated with 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (binap) or 2,3‐bis(diphenylphosphino)butane (chiraphos) gave high yields and high selectivities in a range of 91–99 % ee at 30 °C in a basic dioxane/water solution. The corresponding reaction of unsaturated esters, such as methyl crotonate, had strong resistance under analogous conditions, but the 1,4‐adduct was obtained in 70 % yield and with 94 % ee when more electron‐deficient phenyl crotonate was used as the substrate. 相似文献
13.
Xiaodong Jia Xiangning Chen Congde Huo Fangfang Peng Chang Qing Xicun Wang 《中国化学》2012,30(7):1504-1510
A multicomponent double Mannich reaction of amines, aldehydes and ketones was efficiently catalyzed by molecular iodine, producing a series of 4‐piperidones in a stereoselective way. A variety of amines, aldehydes and ketones were tolerated in this tandem process, including those with labile functinal groups. Further investigation of the reaction between alkyl‐imines and ketones showed that imines from amines and ketones were formed in situ and isomerized to enamine in the presence of molecular iodine to accelerate the corresponding Mannich addition. 相似文献
14.
Isosteviol‐amino acid conjugates were synthesized and used as chiral catalysts for the asymmetric three‐component Mannich reaction with hydroxyacetone as donor molecule. Good yields (up to 98%) and excellent stereoselectivities (up to 97:3 dr and 99% ee) were achieved in a short reaction time. In addition, syn‐ or anti‐configurations of α‐hydroxy‐β‐amino carbonyl compounds were obtained as main products with different chiral catalysts. 相似文献
15.
A highly enantio‐ and diastereoselective Mannich reaction of cyclic N‐acyl ketimines generated in situ from 3‐hydroxyisoindolin‐1‐ones with cyclic enones has been accomplished using a chiral phosphoric acid catalyst to afford the chiral isoindalinone derivatives in high yields with excellent enantioselectivities (upto 97 % ee). This is the first report on the synthesis of chiral isoindolin‐1‐ones bearing adjacent quaternary and tertiary stereogenic centers. 相似文献
16.
2,4‐Bis‐(4‐methoxyphenyl)‐1,3,2,4‐dithiadiphosphetane‐2,4‐disulfide (Lawesson's reagent) ( 1 ) reacted with 2‐hydrazino‐3‐methyl‐quinoxaline ( 2 ) to give [1,2,4,3]‐triazaphospholo[4,5‐a]quinoxaline derivative 3 . The Mannich reaction using different amines on compound 3 gave Mannich bases 4a–d . Also, compound 3 reacted with formaldehyde to give the corresponding 2‐hydroxymethyl derivative 5 , which upon reaction with thionyl chloride gave the corresponding chloromethyl derivative 6 . Treatment of compound 6 with some thiols yielded the corresponding sulfides 7a–d . Acylation of compound 3 gave acylated compounds 8a,b . Compound 9 , which was prepared through the reaction of compound 3 with ethyl cyanoacetate, was investigated as a starting material for the synthesis of some new heterocyclic systems 10–13 . Also, reaction of compound 9 with carbon disulfide and 2 equivalents of methyl iodide in a one‐pot reaction yielded the corresponding ketene‐S,S‐acetal 14 , which in turn reacted with bidentates to give some new heterocycles 15–17 . © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:520–529, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20473 相似文献
17.
Xu Liu Zhaobin Han Zheng Wang Kuiling Ding 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(7):2009-2013
Optically active medium‐sized cyclic carbonyl compounds bearing an α‐chiral carbon center are of interest in pharmaceutical sciences and asymmetric synthesis. Herein, SpinPhox/IrI catalysts have been demonstrated to be highly enantioselective in the asymmetric hydrogenation of the CC bonds in the exocyclic α,β‐unsaturated cyclic carbonyls, including a broad range of α‐alkylidene lactams, unsaturated cyclic ketones, and lactones. It is noteworthy that the procedure can be successfully used in the asymmetric hydrogenation of the challenging α‐alkylidenelactam substrates with six‐ or seven‐membered rings, thus affording the corresponding optically active carbonyl compounds with an α‐chiral carbon center in generally excellent enantiomeric excesses (up to 98 % ee). Synthetic utility of the protocol has also been demonstrated in the asymmetric synthesis of the anti‐inflammatory drug loxoprofen and its analogue, as well as biologically important ε‐aminocaproic acid derivatives. 相似文献
18.
Palladium‐Catalyzed One‐Pot Three‐ or Four‐Component Coupling of Aryl Iodides,Alkynes, and Amines through CN Bond Cleavage: Efficient Synthesis of Indole Derivatives 下载免费PDF全文
Wei Hao Weizhi Geng Prof. Dr. Wen‐Xiong Zhang Prof. Dr. Zhenfeng Xi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(9):2605-2612
An efficient synthesis of N‐substituted indole derivatives was realized by combining the Pd‐catalyzed one‐pot multicomponent coupling approach with cleavage of the C(sp3)?N bonds. Three or four components of aryl iodides, alkynes, and amines were involved in this coupling process. The cyclopentadiene–phosphine ligand showed high efficiency. A variety of aryl iodides, including cyclic and acyclic tertiary amino aryl iodides, and substituted 1‐bromo‐2‐iodobenzene derivatives could be used. Both symmetric and unsymmetric alkynes substituted with alkyl, aryl, or trimethylsilyl groups could be applied. Cyclic secondary amines such as piperidine, morpholine, 4‐methylpiperidine, 1‐methylpiperazine, 2‐methylpiperidine, and acyclic amines including secondary and primary amines all showed good reactivity. Further application of the resulting indole derivatives was demonstrated by the synthesis of benzosilolo[2,3‐b]indole. 相似文献
19.
Octahedral Chiral‐at‐Metal Iridium Catalysts: Versatile Chiral Lewis Acids for Asymmetric Conjugate Additions 下载免费PDF全文
Xiaodong Shen Haohua Huo Chuanyong Wang Bo Zhang Dr. Klaus Harms Prof. Dr. Eric Meggers 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9720-9726
Octahedral iridium(III) complexes containing two bidentate cyclometalating 5‐tert‐butyl‐2‐phenylbenzoxazole ( IrO ) or 5‐tert‐butyl‐2‐phenylbenzothiazole ( IrS ) ligands in addition to two labile acetonitrile ligands are demonstrated to constitute a highly versatile class of asymmetric Lewis acid catalysts. These complexes feature the metal center as the exclusive source of chirality and serve as effective asymmetric catalysts (0.5–5.0 mol % catalyst loading) for a variety of reactions with α,β‐unsaturated carbonyl compounds, namely Friedel–Crafts alkylations (94–99 % ee), Michael additions with CH‐acidic compounds (81–97 % ee), and a variety of cycloadditions (92–99 % ee with high d.r.). Mechanistic investigations and crystal structures of an iridium‐coordinated substrates and iridium‐coordinated products are consistent with a mechanistic picture in which the α,β‐unsaturated carbonyl compounds are activated by two‐point binding (bidentate coordination) to the chiral Lewis acid. 相似文献
20.
Pauline Chaumont‐Olive Mathieu Rouen Gabriella Barozzino‐Consiglio Amel BenAbdeladhim Jacques Maddaluno Anne Harrison‐Marchand 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(10):3225-3229
An enantioselective aryl transfer is promoted using chiral tricoordinated lithium amido aryl zincates that are easily accessible reagents and whose chiral appendage is simply recovered for reuse. The arylation reaction is run in good yields (60 % average on twenty substrates) and high enantiomeric excesses (95 % ee average). This occurs whatever the ortho, meta, or para substituent borne by the substrate and a complete chemoselectivity is observed with respect to the aldehyde function. Sensitive groups such as nitriles, esters, ketones, and enolisable substrates resist to the action of the ate reagent, warranting a large scope to this methodology. 相似文献