共查询到20条相似文献,搜索用时 578 毫秒
1.
Ke Shen Xiaohua Liu Dr. Ke Zheng Wei Li Xiaolei Hu Lili Lin Dr. Xiaoming Feng Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(12):3736-3742
A direct catalytic asymmetric aldol‐type reaction of 3‐substituted‐2‐oxindoles with glyoxal derivatives and ethyl trifluoropyruvate, catalyzed by a chiral N,N′‐dioxide–Sc(OTf)3 (Tf=trifluoromethanesulfonyl) complex, has been developed that tolerates a wide range of substrates. The reaction proceeds in good yields and excellent enantioselectivities (up to 93 % yield, 99:1 diastereomeric ratio (dr), and >99 % enantiomeric excess (ee)) under mild conditions, to deliver 3‐(α‐hydroxy‐β‐carbonyl) oxindoles with vicinal quaternary–tertiary or quaternary–quaternary stereocenters. Even with 1 mol % catalyst loading or on scaleup (10 mmol of starting material), maintenance of ee was observed, which showed the potential value of the catalyst system. In studies probing the reaction mechanism, a positive nonlinear effect was observed and ScIII‐based enolate intermediates were detected by using ESIMS. On the basis of the experimental results and previous reports, a possible catalytic cycle was assumed. 相似文献
2.
A Metal‐free Approach to 3‐Aryl‐3‐hydroxy‐2‐oxindoles by Treatment of 3‐Acyloxy‐2‐oxindoles with Diaryliodonium Salts 下载免费PDF全文
A mild, metal‐free approach has been realized for the facile construction of highly valuable 3‐(hetero)aryl‐3‐hydroxy‐2‐oxindoles. Direct arylations of 3‐acyloxy‐2‐oxindoles with diaryliodonium salts as arylation reagents are implemented in the presence of K2CO3 at room temperature without using an organometallic promoter to deliver an array of 3‐(hetero)aryl‐3‐hydroxy‐2‐oxindoles in good yields. 相似文献
3.
Prof. Dr. Yasunori Yamamoto Masaaki Yohda Tomohiko Shirai Prof. Dr. Hajime Ito Prof. Dr. Norio Miyaura 《化学:亚洲杂志》2012,7(10):2446-2449
A chiral O‐linked C2‐symmetric bidentate phosphoramidite (Me‐BIPAM) was found to be efficient for the ruthenium‐catalyzed addition of arylboronic acids to isatins. Asymmetric synthesis of 3‐aryl‐3‐hydroxy‐2‐oxindoles by 1,2‐addition of arylboronic acids to isatins was carried out in the presence of [RuCl2(PPh3)3]/(R,R)‐Me‐BIPAM and KF, resulting in an enantioselectivity as high as 90 % ee. It was found that the reaction with N‐protected isatins proceeds with high yields and good enantioselectivities. The best protective groups on the nitrogen atom were different depending on the substituents on the aromatic ring. The use of a N‐benzyl group resulted in excellent enantioselectivities in many substrates compared with other groups. 相似文献
4.
3‐Alkyl/aryl‐3‐ureido‐1H,3H‐quinoline‐2,4‐diones ( 2 ) and 3a‐alkyl/aryl‐9b‐hydroxy‐3,3a,5,9b‐tetrahydro‐1H‐imidazo[4,5‐c]quinoline‐2,4‐diones ( 3 ) react in boiling concentrated HCl to give 5‐alkyl/aryl‐4‐(2‐aminophenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ones ( 6 ). The same compounds were prepared by the same procedure from 2‐alkyl/aryl‐3‐ureido‐1H‐indoles ( 4 ), which were obtained from the reaction of 3‐alkyl/aryl‐3‐aminoquinoline‐2,4(1H,3H)‐diones ( 1 ) with 1,3‐diphenylurea or by the transformation of 3a‐alkyl/aryl‐9b‐hydroxy‐3,3a,5,9b‐tetrahydro‐1H‐imidazo[4,5‐c]quinoline‐2,4‐diones ( 3 ) and 5‐alkyl/aryl‐4‐(2‐aminophenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ones ( 6 ) in boiling AcOH. The latter were converted into 1,3‐bis[2‐(2‐oxo‐2,3‐dihydro‐1H‐imidazol‐4‐yl)phenyl]ureas ( 5 ) by treatment with triphosgene. All compounds were characterized by 1H‐ and 13C‐NMR and IR spectroscopy, as well as atmospheric pressure chemical‐ionisation mass spectra. 相似文献
5.
《Journal of heterocyclic chemistry》2017,54(2):1311-1317
p‐Toluenesulfonic acid mediated formal [3+3] cyclization of 3‐indolylmethanols with 3‐isothiocyanato oxindoles was realized. This transformation allowed for the synthesis of a series of novel tetrahydro‐β‐carboline‐1‐thione spirooxindoles in moderate to excellent yields (up to 99%) with generally good diastereoselectivities (up to >20:1). The structure of one product was determined by an X‐ray crystal structural analysis. 相似文献
6.
Yang‐Zi Liu Zhongao Wang Zesheng Huang Xing Zheng Wu‐Lin Yang Wei‐Ping Deng 《Angewandte Chemie (International ed. in English)》2020,59(3):1238-1242
The palladium‐catalyzed asymmetric [4+3] cyclization of trimethylenemethane donors with benzofuran‐derived azadienes furnishes chiral benzofuro[3,2‐b]azepine frameworks in high yields (up to 98 %) with exclusive regioselectivities and excellent stereoselectivities (up to >20:1 d.r., >99 % ee). This catalytic asymmetric [4+3] cyclization of Pd‐trimethylenemethane can enrich the arsenal of Pd‐TMM reactions in organic synthesis. In addition, this strategy provides an alternative approach to chiral azepines by a transition‐metal‐catalyzed asymmetric [4+3] cyclization. 相似文献
7.
Yu‐Hua Liao Xiong‐Li Liu Dr. Zhi‐Jun Wu Prof. Xi‐Lin Du Prof. Dr. Xiao‐Mei Zhang Prof. Dr. Wei‐Cheng Yuan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(21):6679-6687
An asymmetric conjugate addition of 3‐monosubstituted oxindoles to a range of (E)‐1,4‐diaryl‐2‐buten‐1,4‐diones, catalyzed by commercially available cinchonine, is described. This organocatalytic asymmetric reaction affords a broad range of 3,3′‐disubstituted oxindoles that contain a 1,4‐dicarbonyl moiety and vicinal quaternary and tertiary stereogenic centers in high‐to‐excellent yields (up to 98 %), with excellent diastereomeric and moderate‐to‐high enantiomeric ratios (up to 99:1 and 95:5, respectively). Subsequently, cyclization of the 1,4‐dicarbonyl moiety in the resultant Michael adducts under different Paal–Knorr conditions results in two new kinds of 3,3′‐disubstituted oxindoles—3‐furanyl‐ and 3‐pyrrolyl‐3‐alkyl‐oxindoles—in high yields and good enantioselectivities. Notably, the studies presented here sufficiently confirm that this two‐step strategy of sequential conjugate addition/Paal–Knorr cyclization is not only an attractive method for the indirect enantioselective heteroarylation of 3‐alkyloxindoles, but also opens up new avenues toward asymmetric synthesis of structurally diverse 3,3′‐disubstituted oxindole derivatives. 相似文献
8.
Methyl (2E,4R)‐4‐hydroxydec‐2‐enoate, methyl (2E,4S)‐4‐hydroxydec‐2‐enoate, and ethyl (±)‐(2E)‐4‐hydroxy[4‐2H]dec‐2‐enoate were chemically synthesized and incubated in the yeast Saccharomyces cerevisiae. Initial C‐chain elongation of these substrates to C12 and, to a lesser extent, C14 fatty acids was observed, followed by γ‐decanolactone formation. Metabolic conversion of methyl (2E,4R)‐4‐hydroxydec‐2‐enoate and methyl (2E,4S)‐4‐hydroxydec‐2‐enoate both led to (4R)‐γ‐decanolactone with >99% ee and 80% ee, respectively. Biotransformation of ethyl (±)‐(2E)‐4‐hydroxy(4‐2H)dec‐2‐enoate yielded (4R)‐γ‐[2H]decanolactone with 61% of the 2H label maintained and in 90% ee indicating a stereoinversion pathway. Electron‐impact mass spectrometry analysis (Fig. 4) of 4‐hydroxydecanoic acid indicated a partial C(4)→C(2) 2H shift. The formation of erythro‐3,4‐dihydroxydecanoic acid and erythro‐3‐hydroxy‐γ‐decanolactone from methyl (2E,4S)‐4‐hydroxydec‐2‐enoate supports a net inversion to (4R)‐γ‐decanolactone via 4‐oxodecanoic acid. As postulated in a previous work, (2E,4S)‐4‐hydroxydec‐2‐enoic acid was shown to be a key intermediate during (4R)‐γ‐decanolactone formation via degradation of (3S,4S)‐dihydroxy fatty acids and precursors by Saccharomyces cerevisiae. 相似文献
9.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(1):344-348
Naphthols and 3‐trifluoroethylidene oxindoles were found to undergo an asymmetric Friedel–Crafts alkylation/lactonization reaction, catalyzed by only 2.5 mol % of a quinine‐derived squaramide catalyst, to afford the corresponding α‐aryl‐β‐trifluoromethyl dihydrocoumarin derivatives in high yields (up to 99 %) with excellent enantio‐ and diastereoselectivities (up to 98 % ee , >20:1 d.r.). Importantly, the lactonization proceeded by nucleophilic attack of the naphthol hydroxy group at the amide motif of the oxindoles under mild reaction conditions. This protocol represents a new strategy for the formation of dihydrocoumarins by an efficient intramolecular amide C−N bond‐cleavage and esterification process. 相似文献
10.
Cationic Ir/Me‐BIPAM‐Catalyzed Asymmetric Intramolecular Direct Hydroarylation of α‐Ketoamides 下载免费PDF全文
Tomohiko Shirai Prof. Dr. Hajime Ito Prof. Dr. Yasunori Yamamoto 《Angewandte Chemie (International ed. in English)》2014,53(10):2658-2661
Asymmetric intramolecular direct hydroarylation of α‐ketoamides gives various types of optically active 3‐substituted 3‐hydroxy‐2‐oxindoles in high yields with complete regioselectivity and high enantioselectivities (84–98 % ee). This is realized by the use of the cationic iridium complex [Ir(cod)2](BArF4) and the chiral O‐linked bidentate phosphoramidite (R,R)‐Me‐BIPAM. 相似文献
11.
The catalytic asymmetric [3+2] cycloaddition of α‐ketoesters with 2‐nitrovinylindoles and 2‐nitrovinyl‐ pyrroles has been established. This strategy allowed the construction of structurally diverse pyrrolo[1,2‐a]indoles bearing three contiguous stereocenters in generally high yields and good to excellent stereoselectivities (up to 98% yield, > 98 : 2 dr, 99% ee). The efficient synthesis of tetracyclic psychotropic compound analogue via the derivatization of cycloadduct showed the great synthetic potential of this strategy. 相似文献
12.
Efficient Synthesis of Differentiated syn‐1,2‐Diol Derivatives by Asymmetric Transfer Hydrogenation–Dynamic Kinetic Resolution of α‐Alkoxy‐Substituted β‐Ketoesters 下载免费PDF全文
Dr. Laure Monnereau Dr. Damien Cartigny Dr. Michelangelo Scalone Dr. Tahar Ayad Dr. Virginie Ratovelomanana‐Vidal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11799-11806
Asymmetric transfer hydrogenation was applied to a wide range of racemic aryl α‐alkoxy‐β‐ketoesters in the presence of well‐defined, commercially available, chiral catalyst RuII–(N‐p‐toluenesulfonyl‐1,2‐diphenylethylenediamine) and a 5:2 mixture of formic acid and triethylamine as the hydrogen source. Under these conditions, dynamic kinetic resolution was efficiently promoted to provide the corresponding syn α‐alkoxy‐β‐hydroxyesters derived from substituted aromatic and heteroaromatic aldehydes with a high level of diastereoselectivity (diastereomeric ratio (d.r.)>99:1) and an almost perfect enantioselectivity (enantiomeric excess (ee)>99 %). Additionally, after extensive screening of the reaction conditions, the use of RuII‐ and RhIII‐tethered precatalysts extended this process to more‐challenging substrates that bore alkenyl‐, alkynyl‐, and alkyl substituents to provide the corresponding syn α‐alkoxy‐β‐hydroxyesters with excellent enantiocontrol (up to 99 % ee) and good to perfect diastereocontrol (d.r.>99:1). Lastly, the synthetic utility of the present protocol was demonstrated by application to the asymmetric synthesis of chiral ester ethyl (2S)‐2‐ethoxy‐3‐(4‐hydroxyphenyl)‐propanoate, which is an important pharmacophore in a number of peroxisome proliferator‐activated receptor α/γ dual agonist advanced drug candidates used for the treatment of type‐II diabetes. 相似文献
13.
Palladium‐Catalyzed Carbonylative α‐Arylation of 2‐Oxindoles with (Hetero)aryl Bromides: Efficient and Complementary Approach to 3‐Acyl‐2‐oxindoles 下载免费PDF全文
Zhong Lian Stig D. Friis Prof. Dr. Troels Skrydstrup 《Angewandte Chemie (International ed. in English)》2014,53(36):9582-9586
An efficient Pd‐catalyzed carbonylative α‐arylation of 2‐oxindoles with aryl and heteroaryl bromides for the one‐step synthesis of 3‐acyl‐2‐oxindoles has been developed. This reaction proceeds efficiently under mild conditions and is complementary to the more common oxindole forming reactions. The transformation only requires a mild base and provides good to excellent yields even with heteroaromatic substrates. Employing a near stoichiometric amount of 13COgen, the methodology was easily extended to [13C] acyl labeling. The general applicability of the reaction conditions was demonstrated in the synthesis of a structure related to the pharmaceutically active 3‐acyl‐2‐oxindoles, tenidap. 相似文献
14.
Enantioselective Cascade Michael Addition/Cyclization Reactions of 3‐Nitro‐2H‐Chromenes with 3‐Isothiocyanato Oxindoles: Efficient Synthesis of Functionalized Polycyclic Spirooxindoles 下载免费PDF全文
Fen Tan Dr. Liang‐Qiu Lu Qing‐Qing Yang Wei Guo Qiao Bian Prof. Dr. Jia‐Rong Chen Prof. Dr. Wen‐Jing Xiao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(12):3415-3420
An unprecedented Zn(OTf)2‐catalyzed asymmetric Michael addition/cyclization cascade of 3‐nitro‐2H‐chromenes with 3‐isothiocyanato oxindoles has been disclosed. This transformation provides an efficient access to various synthetically important polycyclic spirooxindoles in a highly stereoselective manner under mild conditions (72–99 % yields, up to >95:5 d.r. and >99 % ee). The reaction leads to the formation of three consecutive stereocenters, including 1,3‐nonadjacent tetrasubstituted carbon stereocenters, in a single operation. A bifunctional activation model of the chiral Zn(OTf)2/bis(oxazoline) complex was proposed based on control experiments, wherein the ZnII moiety serves as a Lewis acid and the N atom of the free NH group acts as a Lewis base by a hydrogen‐bonding interaction. 相似文献
15.
Rosa M. Claramunt Dionisia Sanz Concepción López Elena Pinilla M. Rosario Torres José Elguero Pierre Nioche C. S. Raman 《Helvetica chimica acta》2009,92(10):1952-1962
The existence of polymorphism in parent indazolin‐3‐one (=1,2‐dihydro‐3H‐indazol‐3‐one; 1 ) is reported as well as an X‐ray and NMR CPMAS study establishing that its 7‐nitro derivative 2 exists as the 3‐hydroxy tautomer. Absolute shieldings calculated at the GIAO/B3LYP/6‐311++G(d,p) level were used to determine the tautomeric oxo/hydroxy equilibrium in solution, i.e., always the 1H‐indazol‐3‐ol tautomer predominates. 相似文献
16.
The title compounds, the P(3)‐axially and P(3)‐equatorially substituted cis‐ and trans‐configured 9‐benzyl‐3‐fluoro‐2,4‐dioxa‐9‐aza‐3‐phosphadecalin 3‐oxides (=9‐benzyl‐3‐fluoro‐2,4‐dioxa‐9‐aza‐3‐phosphabicyclo[4.4.0]decane 3‐oxides=7‐benzyl‐2‐fluorohexahydro‐4H‐1,3,2‐dioxaphosphorino[4,5‐c]pyridine 2‐oxides) were prepared (ee >99%) and fully characterized (Schemes 2 and 4). The absolute configurations were deduced from that of their precursors, the enantiomerically pure ethyl 1‐benzyl‐3‐hydroxypiperidine‐4‐carboxylates and 1‐benzyl‐3‐hydroxypiperidine‐4‐methanols which were unambiguously assigned. Being configuratively fixed and conformationally constrained phosphorus analogues of acetylcholine, the title compounds represent acetylcholine mimetics and are suitable probes for the investigation of molecular interactions with acetylcholinesterase. As determined by kinetic methods, all of the compounds are moderate irreversible inhibitors of the enzyme. 相似文献
17.
Antonín Klásek Antonín Lyčka Michal Rouchal Ondřej Rudolf Aleš Růžička 《Helvetica chimica acta》2014,97(5):595-612
3‐Aminoquinoline‐2,4‐diones were stereoselectively reduced with NaBH4 to give cis‐3‐amino‐3,4‐dihydro‐4‐hydroxyquinolin‐2(1H)‐ones. Using triphosgene (=bis(trichloromethyl) carbonate), these compounds were converted to 3,3a‐dihydrooxazolo[4,5‐c]quinoline‐2,4(5H,9bH)‐diones. The deamination of the reduction products using HNO2 afforded mixtures of several compounds, from which 3‐alkyl/aryl‐2,3‐dihydro‐1H‐indol‐2‐ones and their 3‐hydroxy and 3‐nitro derivatives were isolated as the products of the molecular rearrangement. 相似文献
18.
Autoxidation/Aldol Tandem Reaction of 2‐Oxindoles with Ketones: A Green Approach for the Synthesis of 3‐Hydroxy‐2‐Oxindoles 下载免费PDF全文
Qing‐Bao Zhang Wen‐Liang Jia Yong‐Liang Ban Yong Zheng Prof. Dr. Qiang Liu Prof. Dr. Li‐Zhu Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(8):2595-2598
In the presence of tetrabutylammonium fluoride and molecular sieves (MS) 4 Å in DMF, an efficient autoxidation reaction of 2‐oxindoles with ketones under air at room temperature has been developed. This approach may provide a green, practical, and metal‐free protocol for a wide range of biologically important 3‐hydroxy‐3‐(2‐oxo‐alkyl)‐2‐oxindoles. 相似文献
19.
Ying‐Chun Chen Jin‐Gen Deng Tong‐Fei Wu Xta Cui Yao‐Zhong Jiang Michael C. K. Choi Albert S. C. Chan 《中国化学》2001,19(8):807-810
Asymmetric reduction of 1, 3‐diones catalyzed by (S, S)‐TsD‐PEN‐Ru(II) complex in a mixture of formic add‐triethylamine proceeded with a substrate/catalyst molar ratio of 100 to give (S, S)‐l,3‐diols with excellent diastereomeric (98.6% de) and enantiomeric purities ( > 99% ee). Other C2‐symmetric diols were also obtained in almost quantitative yields with high diastereomeric (80.0%‐84.2% de) and enantiomeric purities ( > 99% ee). 相似文献
20.
Organocatalytic Asymmetric Friedel–Crafts Reaction of Sesamol with Isatins: Access to Biologically Relevant 3‐Aryl‐3‐hydroxy‐2‐oxindoles 下载免费PDF全文
Dr. Akshay Kumar Jasneet Kaur Dr. Pankaj Chauhan Prof. Dr. Swapandeep Singh Chimni 《化学:亚洲杂志》2014,9(5):1305-1310
The Friedel–Crafts reaction of electron‐rich phenols with isatins was developed by employing bifunctional thiourea–tertiary amine organocatalysts. Cinchona alkaloid derived thiourea epiCDT‐ 3 a efficiently catalyzed the Friedel–Crafts‐type addition of phenols to isatin derivatives to provide 3‐aryl‐3‐hydroxy‐2‐oxindoles 7 and 9 in good yield (80–95 %) with good enantiomeric excess (83–94 %). Friedel–Crafts adduct 7 t was subjected to a copper(I)‐catalyzed azide–alkyne cycloaddition to obtain biologically important 3‐aryl‐3‐hydroxy‐2‐oxindole 11 in good enantiomeric excess and having a 1,2,3‐triazole moiety. 相似文献