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1.
Mohammad Hosein Sayahi Seyyed Jafar Saghanezhad Saeed Bahadorikhalili Mohammad Mahdavi 《应用有机金属化学》2019,33(1)
A novel methodology is presented for the synthesis of 3‐substituted 2‐thioxo‐2,3‐dihydroquinazolin‐4(1H)‐one derivatives based on an efficient tandem multicomponent reaction using copper bromide as catalyst. This methodology is based on the multicomponent one‐pot reaction of methyl 2‐bromobenzoate, phenylisothiocyanate derivatives and sodium azide in the presence of copper bromide and l ‐proline under basic conditions. To show the generality of the method, various phenylisothiocyanates bearing electron‐donating or electron‐withdrawing functionalities were used and the desired products were obtained in high isolated yields. 相似文献
2.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(47):15226-15230
A diastereoselective two‐step strategy for the synthesis of densely functionalized 1‐halocyclopentenes with several chiral centers has been developed. In the first step, a multicomponent alkynyl halo‐Prins reaction joins an enyne, a carbonyl derivative, and either a chloride, bromide, or iodide to produce a cyclic ether intermediate. In the subsequent step, the intermediate is ionized to generate a halopentadienyl cation, which undergoes an interrupted halo‐Nazarov cyclization. The products contain three new contiguous stereogenic centers, generated with a high level of stereocontrol, as well as a vinyl halide allowing for additional functionalization. The strategy creates two new carbon–carbon bonds, one carbon–halide bond, and one carbon–oxygen bond. 相似文献
3.
Chi He Chenlong Zhu Bingnan Wang Prof. Dr. Hanfeng Ding 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15053-15060
In this study, a concise and stereoselective approach for the divergent total synthesis of (?)‐indoxamycins A–F is described. The key steps of the strategy include an Ireland–Claisen rearrangement, an enantioselective 1,6‐enyne reductive cyclization, and a tandem 1,2‐addition/oxa‐Michael/methylenation reaction. The relative and absolute configuration of these natural products has been unambiguously elucidated, and their cytotoxic activities against HT‐29 and A‐549 tumor cell lines are also reported. 相似文献
4.
Self‐Relay Gold(I)‐Catalyzed Pictet–Spengler/Cyclization Cascade Reaction for the Rapid Elaboration of Pentacyclic Indole Derivatives
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Valérian Gobé Dr. Pascal Retailleau Dr. Xavier Guinchard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17587-17590
Gold‐catalyzed cascade reactions allow the rapid elaboration of pentacyclic indolo[2,3‐a]quinolizidines from N‐allyl tryptamines and ortho‐alkynylarylaldehydes. The tandem process combines a gold‐catalyzed Pictet‐Spengler reaction and a cyclization occurring concomitantly with an allyl transfer from the nitrogen atom to the stilbene function. Various substituted allyls were successfully transferred, furnishing the products in yields typically ranging from 60–98 % in high diastereoselectivity. Tryptamines bearing a butenol chain undergo an additional cyclization to chiral hemiaminals in high diastereoselectivities. 相似文献
5.
An unprecedented copper‐promoted tandem coupling and intramolecular cyclization reaction is disclosed. This strategy offers a simple and promising method for accessing 2,4,6‐trisubstituted naphthalenes. A reaction mechanism involving initial formation of diynes followed by a 6‐exo‐dig cyclization and subsequent rearrangement is proposed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
6.
By a one‐pot tandem Ugi multicomponent reaction (MCR)/click reaction sequence not requiring protecting groups, 1H‐1,2,3‐triazole‐modified Ugi‐reaction products 6a – 6n (Scheme 1 and Table 2), 7a – 7b (Table 4), and 8 (Scheme 2) were synthesized successfully. i.e., terminal, side‐chain, or both side‐chain and terminal triazole‐modified Ugi‐reaction products as potential amino acid units for peptide syntheses. Different catalyst systems for the click reaction were examined to find the optimal reaction conditions (Table 1, Scheme 1). Finally, an efficient Ugi MCR+Ugi MCR/click reaction strategy was elaborated in which two Ugi‐reaction products were coupled by a click reaction, thus incorporating the triazole fragment into the center of peptidomimetics (Scheme 3). Thus, the Ugi MCR/click reaction sequence is a convenient and simple approach to different 1H‐1,2,3‐triazole‐modified amino acid derivatives and peptidomimetics. 相似文献
7.
Insights into the Gold‐Catalyzed Propargyl Ester Rearrangement/Tandem Cyclization Sequence: Radical versus Gold Catalysis—Myers–Saito‐ versus Schmittel‐Type Cyclization
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Dipl.‐Chem. Eva Rettenmeier Dr. Max M. Hansmann Alexander Ahrens Katharina Rübenacker Tapish Saboo Joy Massholder Christian Meier Dr. Matthias Rudolph Prof. Dr. A. Stephen K. Hashmi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(41):14401-14409
A detailed study of the gold‐catalyzed tandem 1,3‐carboxy migration/allene–enyne cycloisomerization was undertaken. It was found that after the initial allene formation the selectivity of the reaction is strongly influenced by the polarization of the remaining alkyne. Depending on the substitution pattern of the starting diynes, either a Schmittel‐ or a Myers–Saito‐type cyclization was triggered. The 6‐endo‐dig Myers–Saito‐type cyclization gave access to benzo[b]fluorenes, while the Schmittel pathway (5‐exo‐dig) delivered benzofulvenes as final products. In special cases a yet unknown pathway was opened by the ambiphilic nature of the allene moiety. In these cases completely different products were obtained by the nucleophilic attack of the alkyne moiety onto the allene that can also act as an electrophile. Mechanistic studies revealed that diradical pathways can be ruled out for this type of tandem cyclization reactions and it is shown that both steps of the reaction cascade are catalyzed by the gold complex. 相似文献
8.
A tandem one‐pot synthesis of polysubstituted 1,3‐thiazines has been developed by reacting with cyanoacetamide and isothiocyanate derivatives to give rise to 2‐cyano‐3‐mercaptoacrylamides, which are trapped in situ by various aldehydes or diversely substituted ketones through intermolecular cyclization, providing polysubstituted 1,3‐thiazine derivatives in short reaction times with good to excellent yields. The salient features of this novel protocol are operational simplicity, accessing the desired products from the readily available starting materials and easy of product isolation and may find wide spread applications in medicinal chemistry. 相似文献
9.
Jhillu Singh Yadav Dandekar Chandrakanth Yerragorla Gopala Rao Kontham Ravindar Basi V. Subba Reddy 《Helvetica chimica acta》2010,93(7):1432-1438
The stereoselective total synthesis of an antiproliferative and antifungal α‐pyrone natural product (6S)‐5,6‐dihydro‐6‐[(2R)‐2‐hydroxy‐6‐phenylhexyl]‐2H‐pyran‐2‐one is described. The key steps involved are the Prins cyclization, Mitsunobu reaction, and ring‐closing metathesis reaction. 相似文献
10.
A Synthetic Approach for Constructing the 3/6/6/5‐Fused Tetracyclic Skeleton of Tenuipesine A
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Jin‐Miao Tian Dr. Xiong Zhao Prof. Dr. Yong‐Qiang Tu Wei Gong Prof. Dr. Fu‐Min Zhang Dr. Shu‐Yu Zhang Prof. Dr. Shao‐Hua Wang 《化学:亚洲杂志》2014,9(3):724-727
An efficient approach toward the 3/6/6/5‐fused tetracyclic skeleton of tenuipesine A has been accomplished. The strategy featured 1) a tandem Mitsunobu and 3,3‐rearrangement reaction yielding the key intermediate 7 with two adjacent all‐carbon quaternary centers with high d.r.; and 2) a tandem DBDMH‐mediated semipinacol rearrangement via a 1,2‐oxygen migration of an allylic hemiketal to construct the highly substituted tetrahydropyran ring. 相似文献
11.
Bo Xu Wen Xun Shaobin Su Hongbin Zhai 《Angewandte Chemie (International ed. in English)》2020,59(38):16475-16479
Cyclopianes are novel diterpenes featuring a highly strained 6/5/5/5 tetracyclic core embedded with 6–8 consecutive stereocenters. The concise total syntheses of (?)‐conidiogenone B, (?)‐conidiogenone, and (?)‐conidiogenol have been accomplished in 14–17 steps. The present work features a HAT‐mediated alkene–nitrile cyclization to access the cis‐biquinane, a Nicholas/Pauson–Khand reaction to construct the linear triquinane, and a Danheiser annulation to afford the congested angular triquinane skeleton. 相似文献
12.
Catalyst‐Free Three‐Component Tandem CDC Cyclization: Convenient Access to Isoindolinones from Aromatic Acid,Amides, and DMSO by a Pummerer‐Type Rearrangement
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Peng‐Min Wang Fan Pu Ke‐Yan Liu Prof. Dr. Chao‐Jun Li Prof. Dr. Zhong‐Wen Liu Dr. Xian‐Ying Shi Juan Fan Dr. Ming‐Yu Yang Prof. Dr. Jun‐Fa Wei 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(18):6262-6267
A catalyst‐free multicomponent CDC reaction is rarely reported, especially for the intermolecular tandem CDC cyclization, which represents an important strategy for constructing cyclic compounds. Herein, a three‐component tandem CDC cyclization by a Pummerer‐type rearrangement to afford biologically relevant isoindolinones from aromatic acids, amides, and DMSO, is described. This intermolecular tandem reaction undergoes a C(sp2)?H/C(sp3)?H cross‐dehydrogenative coupling, C?N bond formation, and intramolecular amidation. A notable feature of this novel protocol is avoiding a catalyst and additive (apart from oxidant). 相似文献
13.
Theoretical study on the reaction mechanisms and stereoselectivities of DABCO‐catalyzed Rauhut–Currier/cyclization reaction of methyl acrylate with 2‐benzoyl‐3‐phenyl‐acrylonitrile
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With the aid of density functional theory (DFT) calculations, we have investigated the mechanisms and stereoselectivities of the tandem cross Rauhut–Currier/cyclization reaction of methyl acrylate R1 with (E)‐2‐benzoyl‐3‐phenyl‐acrylonitrile R2 catalyzed by a tertiary amine DABCO. The results of the DFT calculations indicate that the favorable mechanism (mechanism A) includes three steps: the first step is the nucleophilic attack of DABCO on R1 to form intermediates Int1 and Int1‐1, the second step is the reaction of Int1 and Int1‐1 with R2 to generate intermediate Int2(SS,RR,SR&RS), and the last step is an intramolecular SN2 process to give the final product P(SS,RR,SR&RS) and release catalyst DABCO. The SN2 substitution is computed to be the rate‐determining step, whereas the second step is the stereoselectivity‐determining step. The present study may be helpful for understanding the reaction mechanism of similar tandem reactions. 相似文献
14.
Indium Trichloride (InCl3) Catalyzed Synthesis of Fused 7‐Azaindole Derivatives Using Domino Knoevenagel‐Michael Reaction
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Sakharam B. Dongare Hemant V. Chavan Datta N. Surwase Pravin S. Bhale Yoginath B. Mule Babasaheb P. Bandgar 《中国化学会会志》2016,63(4):323-330
An efficient and high yielding methodology developed for the synthesis of fused 7‐azaindole derivatives via one pot multicomponent assembly process of cyclic 1,3‐dicarbonyls with substituted aldehydes and 5‐amino‐1‐tert‐butyl‐1H‐pyrrole‐3‐carbonitrile. The transformation occurs via domino Knoevenagel‐ Michael reaction followed by intramolecular cyclization in the presence of catalytic amount of InCl3 (10 mol %). Mild reaction conditions, easy isolation of products, and good to excellent yields in a shorter period of time are the silent features of present methodology. Structures of all the newly prepared compounds have been corroborated by various spectroscopic methods. 相似文献
15.
Biswanath Das Avula Satya Kumar Jayprakash Narayan Kumar 《Helvetica chimica acta》2011,94(8):1459-1462
(α‐Aminoalkyl)phosphonates have efficiently been synthesized by multicomponent reaction of aldehydes, amines, and triethyl phosphite in the presence of 2,4,6‐trichloro‐1,3,5‐triazine at room temperature. The products are formed in high yields (83–91%) within 0.5–1 h. 相似文献
16.
Gold‐Catalyzed Cycloisomerization and Diels–Alder Reaction of 1,4,9‐Dienyne Esters to 3 a,6‐Methanoisoindole Esters with Pro‐Inflammatory Cytokine Antagonist Activity
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Dewi Susanti Li‐Juan Liu Dr. Weidong Rao Sheng Lin Prof. Dr. Dik‐Lung Ma Prof. Dr. Chung‐Hang Leung Prof. Dr. Philip Wai Hong Chan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9111-9118
A synthetic method to prepare 3a,6‐methanoisoindole esters efficiently by gold(I)‐catalyzed tandem 1,2‐acyloxy migration/Nazarov cyclization followed by Diels–Alder reaction of 1,4,9‐dienyne esters is described. We also report the ability of one example to inhibit binding of tumor necrosis factor‐α (TNF‐α) to the tumor necrosis factor receptor 1 (TNFR1) site and TNF‐α‐induced nuclear factor κ‐light‐chain‐enhancer of activated B cells (NF‐κB) activation in cell at a half‐maximal inhibitory concentration (IC50) value of 6.6 μM . Along with this is a study showing the isoindolyl derivative to exhibit low toxicity toward human hepatocellular liver carcinoma (HepG2) cells and its possible mode of activity based on molecular modeling analysis. 相似文献
17.
Efficient Access to Bicyclo[4.3.0]nonanes: Copper‐Catalyzed Asymmetric Silylative Cyclization of Cyclohexadienone‐Tethered Allenes
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Zhi‐Tao He Xiao‐Qi Tang Li‐Bo Xie Mian Cheng Ping Tian Prof. Guo‐Qiang Lin 《Angewandte Chemie (International ed. in English)》2015,54(49):14815-14818
The creation of three consecutive chiral carbon centers in one step is achieved using Cu‐catalyzed asymmetric silylative cyclization of cyclohexadienone‐tethered allenes. Through regioselective β‐silylation of the allene and subsequent enantioselective 1,4‐addition to cyclohexadienone, this tandem reaction could afford cis‐hydrobenzofuran, cis‐hydroindole, and cis‐hydroindene frameworks with excellent yields (80–98 %) and enantioselectivities (94–98 % ee) bearing vinylsilane and enone substructures. Meanwhile, this mild transformation is generally compatible with a wide range of functional groups, which allows further conversion of the bicyclic products to bridged and tricyclic ring structures. 相似文献
18.
Gold‐Catalyzed Regiospecific C−H Annulation of o‐Ethynylbiaryls with Anthranils: π‐Extension by Ring‐Expansion En Route to N‐Doped PAHs
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Zhongyi Zeng Hongming Jin Dr. Kohei Sekine Dr. Matthias Rudolph Frank Rominger Prof. Dr. A. Stephen K. Hashmi 《Angewandte Chemie (International ed. in English)》2018,57(23):6935-6939
We describe a novel, short, and flexible approach to diverse N‐doped polycyclic aromatic hydrocarbons (PAHs) through gold‐catalyzed π‐extension of anthranils with o‐ethynylbiaryls as reagents. This strategy uses easily accessible starting materials, is simple due to high step and atom economy, and shows good functional‐group compatibility as well as scale‐up potential. Mechanistically, the tandem reaction is proposed to involve a nucleophilic addition/ring opening/regiospecific C?H annulation/protodeauration sequence terminated by a Friedel–Crafts‐type cyclization. Photophysical studies of the products indicated violet‐blue fluorescence emission with quantum yields up to 0.45. 相似文献
19.
Lei Peng Kai Li Chuandong Xie Shan Li Da Xu Wenling Qin Hailong Yan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(48):17359-17364
A chiral Brønsted base catalyzed asymmetric annulation of ortho‐alkynylanilines has been developed to access axially chiral naphthyl‐C2‐indoles via vinylidene ortho‐quinone methide (VQM) intermediates. This strategy provides a unique organocatalytic atroposelective route to axially chiral aryl‐C2‐indole skeletons with excellent enantioselectivity and functional‐group tolerance. This transformation was applicable to decagram‐scale preparation (50.0 g) with perfect enantioselectivity through simple recrystallization. Moreover, the utility of this reaction was demonstrated by a variety of transformations towards chiral naphthyl‐C2‐indoles for a series of carbon–heteroatom bond formations. Furthermore, the prepared axially chiral naphthyl‐C2‐indoles were applied as a chiral skeleton for organocatalytic aza‐Baylis–Hillman reaction and asymmetric formal [4+2] tandem cyclization to give the corresponding adducts in high yields with improved enantioselectivity and diastereoselectivity. 相似文献
20.
Cobalt‐Catalyzed Tandem C−H Activation/C−C Cleavage/C−H Cyclization of Aromatic Amides with Alkylidenecyclopropanes
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Dr. Mingliang Li Prof. Dr. Fuk Yee Kwong 《Angewandte Chemie (International ed. in English)》2018,57(22):6512-6516
A cobalt‐catalyzed chelation‐assisted tandem C?H activation/C?C cleavage/C?H cyclization of aromatic amides with alkylidenecyclopropanes is reported. This process allows the sequential formation of two C?C bonds, which is in sharp contrast to previous reports on using rhodium catalysts for the formation of C?N bonds. Here the inexpensive catalyst system exhibits good functional‐group compatibility and relatively broad substrate scope. The desired products can be easily transformed into polycyclic lactones with m‐CPBA. Mechanistic studies revealed that the tandem reaction proceeds through a C?H cobaltation, β‐carbon elimination, and intramolecular C?H cobaltation sequence. 相似文献