共查询到20条相似文献,搜索用时 31 毫秒
1.
Prof. Takahide Fukuyama Yuko Ohta Dr. Célia Brancour Kazusa Miyagawa Prof. Ilhyong Ryu Dr. Anne‐Lise Dhimane Prof. Louis Fensterbank Prof. Max Malacria 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7243-7247
We have developed novel Rh‐catalyzed [n+1]‐type cycloadditions of 1,4‐enyne esters, which involve an acyloxy migration as a key step. The efficient preparation of functionalized resorcinols, including biaryl derivatives, from readily available 1,4‐enyne esters and CO was achieved by Rh‐catalyzed [5+1] cycloaddition accompanied by 1,2‐acyloxy migration. When enyne esters had an internal alkyne moiety, the reaction proceeded by a [4+1]‐type cycloaddition involving 1,3‐acyloxy migration, leading to cyclopentenones. 相似文献
2.
Gold‐Catalyzed [2+2+1] Cycloaddition of 1,6‐Diyne Carbonates and Esters with Aldehydes to 4‐(Cyclohexa‐1,3‐dienyl)‐1,3‐dioxolanes
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Dr. Weidong Rao Prof. Dr. Philip Wai Hong Chan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):713-718
A synthetic method to stereoselectively prepare 4‐(cyclohexa‐1,3‐dienyl)‐1,3‐dioxolanes in good to excellent yields by gold(I)‐catalyzed [2+2+1] cycloaddition of 1,6‐diyne carbonates and esters with aldehydes is described. The cascade process involves 1,2‐acyloxy migration followed by cyclopropenation and cycloreversion. This leads to an unprecedented [2+2+1] cycloaddition of the resulting alkenylgold carbenoid species, examples of which are extremely rare, with two aldehyde molecules at catalyst loadings as low as 1 mol %. The usefulness of this cycloisomerization chemistry was further demonstrated by the transformation of one example to the corresponding phenol. 相似文献
3.
Stereoselective Synthesis of 1,2,3‐Triazolooxazine and Fused 1,2,3‐Triazolo‐δ‐Lactone Derivatives
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The stereoselective synthesis of 1,2,3‐triazolooxazine and fused 1,2,3‐triazolo‐δ‐lactone by applying chemoenzymatic methods is described. trans‐2‐Azidocyclohexanol was successfully resolved by Novozyme 435 with an ee value of 99%. Installation of the alkyne moiety on the enantiomerically enriched azidoalcohol by O‐alkylation, followed by intramolecular azide? alkyne [3+2] cycloaddition resulted in the desired 1,2,3‐triazolooxazine derivative. Enantiomerically pure azidocyclohexanol was also subjected to the Huisgen 1,3‐dipolar cycloaddition reaction with dimethylacetylene dicarboxylate, followed by intramolecular cyclization of the corresponding cycloadduct, to furnish a fused 1,2,3‐triazolo‐δ‐lactone. 相似文献
4.
Gold‐Catalyzed Sequential Cyclization of 1‐En‐3,9‐Diyne Esters to Partially Hydrogenated 3H‐Dicyclopenta[a,b]naphthalenes
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Prof. Dr. Weidong Rao Joshua William Boyle Prof. Dr. Philip Wai Hong Chan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6532-6536
A synthetic method that relies on a gold(I)‐catalyzed cycloisomerization of 1‐en‐3,9‐diyne esters to spiro[4.4]non‐2‐ene‐substituted 1,2‐dihydronaphthalenes is described. Robust with a wide variety of substitution patterns tolerated, the reaction provides the first example of a one‐step strategy to construct such novel and architecturally challenging members of the carbocycle family in good to excellent yields. A mechanism is proposed in which the sequential cycloisomerization pathway was thought to involve a gold‐catalyzed 1,3‐acyloxy migration/Nazarov cyclization followed by a formal [4+2] cycloaddition to give the tetracarbocyclic product. 相似文献
5.
Yajun Li Dr. Jiangtao Zhu Lisi Zhang Prof. Dr. Yongming Wu Prof. Dr. Yuefa Gong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(25):8294-8299
A highly efficient method for the synthesis of fluorine‐containing multisubstituted phenanthridines through Rh‐catalyzed alkyne [2+2+2] cycloaddition reactions has been developed. This method exhibits excellent functional‐group compatibility. When a bromodifluoromethyl group, rather than a trifluoromethyl group, was employed in the cycloaddition reaction, more‐complicated polycyclic compounds were obtained through tandem Rh‐catalyzed cycloaddition/C? H difluoromethylenation. This route provides convenient access to fluorine‐containing polycyclic compounds. 相似文献
6.
An Efficient Synthesis of Benzazocines by Gold(I)‐Catalyzed Tandem 1,2‐Acyloxy Shift/[3+2] Cycloaddition of Terminal 1,9‐Enynyl Esters
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Shangbiao Feng Zhengshen Wang Weiwei Zhang Prof. Dr. Xingang Xie Prof. Dr. Xuegong She 《化学:亚洲杂志》2016,11(15):2167-2172
An effective synthesis of structurally diverse benzazocines was accomplished in good to excellent chemical yields (55–82 %) through a gold(I)‐catalyzed cascade reaction involving tandem 1,2‐acyloxy shift/[3+2] cycloaddition of terminal 1,9‐enynyl esters. The reaction proceeds under extremely mild conditions and represents one of the relatively few transition‐metal‐catalyzed intramolecular cycloaddition reactions for the synthesis of benzazocines. 相似文献
7.
Fukuyama T Ohta Y Brancour C Miyagawa K Ryu I Dhimane AL Fensterbank L Malacria M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7243-7247
We have developed novel Rh-catalyzed [n+1]-type cycloadditions of 1,4-enyne esters, which involve an acyloxy migration as a key step. The efficient preparation of functionalized resorcinols, including biaryl derivatives, from readily available 1,4-enyne esters and CO was achieved by Rh-catalyzed [5+1] cycloaddition accompanied by 1,2-acyloxy migration. When enyne esters had an internal alkyne moiety, the reaction proceeded by a [4+1]-type cycloaddition involving 1,3-acyloxy migration, leading to cyclopentenones. 相似文献
8.
Gold(I)‐Catalyzed 1,2‐Acyloxy Migration/[3+2] Cycloaddition of 1,6‐Diynes with an Ynamide Propargyl Ester Moiety: Highly Efficient Synthesis of Functionalized Cyclopenta[b]indoles
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Dr. Jun Liu Ming Chen Liangwei Zhang Prof. Yuanhong Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(3):1009-1013
A gold‐catalyzed cycloisomerization of 1,6‐diynes containing an ynamide propargyl ester or carbonate moiety has been developed that provides an attractive route to a diverse‐substituted 3‐acyloxy‐1,4‐dihydrocyclopenta[b]indoles. Mechanistic studies indicate that the reaction likely proceeds through a competitive 1,2‐OAc migration followed by [3+2] cycloaddition of the vinyl gold–carbenoid intermediate with the pendant triple bond. The synthetic utility of the obtained cyclopenta[b]indole products was demonstrated by their efficient transformations by deprotection or double‐bond isomerization reactions. 相似文献
9.
Rhodium(II)‐Catalyzed Cycloaddition Reactions of Non‐classical 1,5‐Dipoles for the Formation of Eight‐Membered Heterocycles
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Dong Jin Lee Donguk Ko Prof. Eun Jeong Yoo 《Angewandte Chemie (International ed. in English)》2015,54(46):13715-13718
A new type of intermolecular rhodium(II)‐catalyzed [5+3] cycloaddition has been developed. This higher‐order cycloaddition between pyridinium zwitterion 1,5‐dipole equivalents and enol diazoacetates enables the formation of eight‐membered heterocyclic skeletons, which are otherwise difficult to construct. The optimized cycloaddition occurs efficiently under mild conditions with a wide range of pyridinium zwitterions and with high functional‐group tolerance. 相似文献
10.
[2 + 2] Cycloaddition Reactions of Butadienyl Ketene with 1,4‐Diazabuta‐1,3‐dienes: Synthesis of Functionalized Butadienyl‐4‐iminomethyl‐azetidin‐2‐ones and Butenylidene‐butadienyl‐[2,2′‐biazetidine]‐4,4′‐diones
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Deepak Bains Yogesh Kumar Prabhpreet Singh Gaurav Bhargava 《Journal of heterocyclic chemistry》2016,53(5):1665-1669
The reactions of butadienylketene with variety of 1,4‐diazabuta‐1,3‐dienes are studied. The reactions resulted in the formation of previously unknown functionalized cis butadienyl‐4‐iminomethyl‐azetidin‐2‐ones and butenylidene‐butadienyl‐[2,2′‐biazetidine]‐4,4′‐ diones. Butadienyl ketene reacts in [2+2] cycloaddition fashion with both iminic portion of 1,4‐ diazabuta‐1,3‐dienes and competitive [4+2] cycloaddition reaction of 1,4‐diazabuta‐1,3‐dienes as 4π component with butadienyl ketene as 2π component are not observed. 相似文献
11.
Prof. Dr. Kimihiro Komeyama Yuji Okamoto Prof. Dr. Ken Takaki 《Angewandte Chemie (International ed. in English)》2014,53(42):11325-11328
A formal [4+2] cycloaddition of α,α′‐dichloro‐ortho‐xylenes with various alkynes has been developed using a low‐valent cobalt catalyst. The transformation has a wide substrate scope and high functional‐group tolerance and led to 1,4‐dihydronaphthalenes. The formed cycloadducts were easily aromatized with MnO2 under air. A mechanistic investigation suggests that the transformation proceeds through a benzyl cobaltation of alkyne, not the classical Diels–Alder reaction of ortho‐quinodimethanes. This methodology provides a straightforward and streamlined access to linearly expanded π‐conjugated aromatics. 相似文献
12.
Nathalie Fischer‐Durand Daria Lizinska Vincent Gurineau Bogna Rudolf Michle Salmain 《应用有机金属化学》2019,33(4)
Owing to the intrinsic limitations of the conventional bioconjugation methods involving native nucleophilic functions of proteins, we sought to develop alternative approaches to introduce metallocarbonyl infrared labels onto proteins on the basis of the [3 + 2] dipolar azide‐alkyne cycloaddition (AAC). To this end, two cyclopentadienyl iron dicarbonyl (Fp) complexes carrying a terminal or a strained alkyne handle were synthesized. Their reactivity was examined towards a model protein and poly (amidoamine) (PAMAM) dendrimer, both carrying azido groups. While the copper (I)‐catalysed azide‐alkyne cycloaddition (CuAAC) proceeded smoothly with the terminal alkyne metallocarbonyl derivative, labelling by strain‐promoted azide‐alkyne cycloaddition (SPAAC) was less successful in terms of final coupling ratios. Infrared spectral characterization of the bioconjugates showed the presence of two bands in the 2000 cm?1 region, owing to the stretching vibration modes of the carbonyl ligands of the Fp entities. 相似文献
13.
Isolation of an Eleven‐Atom Polydentate Carbon‐Chain Chelate Obtained by Cycloaddition of a Cyclic Osmium Carbyne with an Alkyne
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Dr. Congqing Zhu Dr. Jun Zhu Xiaoxi Zhou Qin Zhu Yuhui Yang Prof. Dr. Ting Bin Wen Prof. Dr. Haiping Xia 《Angewandte Chemie (International ed. in English)》2018,57(12):3154-3157
Carbon ligands have long played an important role in organometallic chemistry. However, previous examples of all‐carbon chelating ligands are limited. Herein, we present a novel complex with an eleven‐atom carbon chain as a polydentate chelating ligand. This species was formed by the [2+2+2] cycloaddition reaction of two equivalents of an alkyne with an osmapentalyne that contains the smallest carbyne bond angle (127.9°) ever observed. Density functional calculations revealed that electron‐donating groups play a key role in the stabilization of this polydentate carbon‐chain chelate. This process is also the first [2+2+2] cycloaddition reaction of an alkyne with a late‐transition‐metal carbyne complex. This study not only enriches the chemistry of polydentate carbon‐chain chelates, but also deepens our understanding of the chelating ability of carbon ligands. 相似文献
14.
A one‐pot four component condensation of isatin, sarcosine, 2‐[2‐oxo‐1‐(prop‐2‐ynyl)indolin‐3‐ylidene]malononitrile and aryl azides has been reported for the synthesis of novel dispirooxindole pyrrolidine linked 1,2,3‐triazole conjugates using Cu(I) as a catalyst in PEG‐400 by stereoselective [3 + 2] azide‐alkyne cycloaddition followed by [3 + 2] azomethine ylide and alkene cycloaddition. Structures have been confirmed by spectral and X‐ray studies. Crystal packing of 5a has also been reported. Rapid reaction, easy work‐up and high yields are the salient features of the present protocol. 相似文献
15.
Chuan‐Hu Lei Dr. De‐Xian Wang Dr. Liang Zhao Prof. Dr. Jieping Zhu Prof. Dr. Mei‐Xiang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(50):16981-16987
Tandem reactions for the efficient synthesis of multifunctionalized 1,2,3,4‐tetrahydropyridines, 2,3‐dihydropyridin‐4(1H)‐ones, and pyridine derivatives have been developed and reaction mechanisms have been investigated. Synthetic cascades are initiated by the Zn(OTf)2‐mediated [5+1] cycloaddition of N‐formylmethyl‐substituted tertiary enamides to isocyanides, thus leading to the versatile heterocyclic enamino imine intermediates. Interception of the intermediates by diastereoselective reduction of imine functionality with Me4NBH(OAc)3 afforded 1,6‐disubstituted trans‐3‐hydroxy‐4‐arylamino‐ or ‐alkylamino‐1,2,3,4‐tetrahydropyridines, whereas acylation of the imino group followed by acidic hydrolysis produced 1,6‐disubstituted 3‐acyloxy‐2,3‐dihydropyridin‐4(1H)‐ones. Aerobic oxidation led to the aromatization followed by intermolecular acyl‐group transfer from the pyridinium nitrogen to the 3‐hydroxy moiety, thereby yielding substituted 3‐acyloxy‐4‐aminopyridines. Synthetic potentials of the resulting products have been demonstrated by expedient and highly stereoselective synthesis of cis,cis‐4,5‐dihydroxy‐2‐phenylpiperidine and trans,trans‐4‐amino‐5‐hydroxy‐2‐phenylpiperidine compounds, which are important in medicinal chemistry, through simple and practical reduction reactions. 相似文献
16.
Palladium‐Catalyzed Reductive [5+1] Cycloaddition of 3‐Acetoxy‐1,4‐enynes with CO: Access to Phenols Enabled by Hydrosilanes
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Li‐Jun Wu Prof. Dr. Ren‐Jie Song Prof. Dr. Shenglian Luo Prof. Dr. Jin‐Heng Li 《Angewandte Chemie (International ed. in English)》2018,57(40):13308-13312
A new palladium‐catalyzed reductive [5+1] cycloaddition of 3‐acetoxy‐1,4‐enynes with CO, enabled by hydrosilanes, has been developed for delivering valuable functionalized phenols. This methodology employs hydrosilanes as the external reagent to facilitate the [5+1] carbonylative benzannulation. The reaction is a conceptually and mechanistically novel carbonylative cycloaddition route for the construction of substituted phenols, through the formation of four new chemical bonds, with excellent functional‐group tolerance. 相似文献
17.
Huamin Wang Junyou Zhang Youshao Tu Junliang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(16):5476-5480
Over the past years, the metal‐catalyzed dearomative cycloaddition of 3‐nitroindoles and 2‐nitrobenzofurans have emerged as a powerful protocol to construct chiral fused heterocyclic rings. However, organocatalytic dearomative reaction of these two classes of heteroarenes has become a long‐standing challenging task. Herein, we report the first example of phosphine‐catalyzed asymmetric dearomative [3+2]‐cycloadditio of 3‐nitroindoles and 2‐nitrobenzofurans, which provide a new, facile, and efficient protocol for the synthesis of chiral 2,3‐fused cyclopentannulated indolines and dihydrobenzofurans by reacting with allenoates and MBH carbonates, respectively through a dearomative [3+2]‐cycloaddition. 相似文献
18.
Cross‐Cycloaddition of Two Different Isocyanides: Chemoselective Heterodimerization and [3+2]‐Cyclization of 1,4‐Diazabutatriene
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Zhongyan Hu Dr. Haiyan Yuan Yang Men Prof. Dr. Qun Liu Prof. Dr. Jingping Zhang Prof. Dr. Xianxiu Xu 《Angewandte Chemie (International ed. in English)》2016,55(25):7077-7080
A new cross‐cycloaddition reaction between a wide range of isocyanides and 2‐isocyanochalcones (or analogues) was developed for the expeditious synthesis of pyrrolo[3,4‐b]indoles under thermal conditions. On the basis of the experimental results and DFT calculations, a mechanism for this domino reaction is proposed involving chemoselective heterodimerization of two different isocyanides to form 1,4‐diazabutatriene intermediates, followed by an intramolecular [3+2]‐cycloaddition and 1,3‐proton shift. 相似文献
19.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(30):8793-8797
Previously reported was that cis‐ene‐vinylcyclopropanes (cis‐ene‐VCPs) underwent Rh‐catalyzed [5+2] reaction to give 5,7‐fused bicyclic products, where vinylcyclopropane (VCP) acts as five‐carbon synthon. Unfortunately, this reaction had very limited scope. Replacing the 2π component of cis‐ene‐VCPs to allene moiety, the corresponding cis‐allene‐VCPs did not undergo the expected normal [5+2] cycloaddition to give 5,7‐fused bicyclic products. Instead, the challenging bicyclo[4.3.1]decane skeleton was obtained via an unprecedented bridged [5+2] cycloaddition. DFT calculations were applied to understand why this bridged [5+2] reaction is favored over the anticipated but not realized normal [5+2] reaction. 相似文献
20.
Osvaldo Gutierrez Jason G. Harrison Ryan P. Pemberton Prof. Dean J. Tantillo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(35):11029-11035
DFT (both B3LYP and M06‐2X), CASSCF, and CASPT2 calculations were used to investigate competing [3, 3] and [3, 5] sigmatropic shifts and intramolecular [4+2] cycloaddition of 1,3,7‐octatriene. In accord with previous results on 1,5‐hexadiene, CASSCF calculations found both stepwise and concerted pathways for the [3, 3] rearrangement. For the competing [3, 5] sigmatropic rearrangement, CASSCF and CASPT2 calculations revealed three stepwise pathways with similar barriers. UB3LYP and UM06‐2X calculations predicted a different potential energy landscape: no stepwise [3, 3] pathway, only two competing [3, 5] sigmatropic shifts, and an intramolecular Diels–Alder cycloaddition/homolytic ring‐opening pathway. Significant lowering of barriers for all rearrangements was predicted for some 1,3,7‐octatrienes with substituents at the 4‐ and 7‐positions. 相似文献