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1.
in this work, the phosphine-catalyzed annulation reactions between modified allylic derivatives and polar 1,1-dicyano-1,3-dienes have been studied. In the catalysis of PPh3 (20 mol%), a [4 + 1 ] annulation reaction is realized between a series of l,l-dicyano-2,4-diaryl-1,3-dienes and ethoxycarbonyl-activated allylic acetate, producing polysubstituted cyclopentenes in modest to excellent yields. It is also observed that the substituents of both 1,3-dienes and allylic derivatives have a significant influence on the annulation mode: under the catalysis of PPh3 or PBu3 (20 mol%), regioselective [3 + 2] annulation products are formed from differently substituted substratcs. 相似文献
2.
Chernyshev E. A. Komalenkova N. G. Yakovleva G. N. Bykovenko V. G. Shcherbinin V. V. Belokon' A. I. 《Russian Journal of General Chemistry》2001,71(9):1438-1442
Studies of the reaction of GeCl4 with acyclic conjugated dienes (1,3-butadiene, 2-methyl-1,3- butadiene, 2,3-dimethyl-1,3-butadiene) and cyclopentadiene in the presence of Si2Cl6 initiator were carried out. With acyclic dienes, corresponding 1,1-dichloro-1-germacyclo-3-pentenes and 1,1-dichloro-1-silacyclo-3- pentenes are preferrably formed. With cyclopentadiene the main reaction products are cyclopentenyltrichlorogermanes and cyclopentenyltrichlorosilanes formed respectively by hydrogermylation and hydrosilylation of the starting diene. The explanation of the established rule is offered. 相似文献
3.
Sudo Y Shirasaki D Harada S Nishida A 《Journal of the American Chemical Society》2008,130(38):12588-12589
1-Methoxy-3-trimethylsiloxy-1,3-butadiene (Danishefsky's diene) is recognized as a synthetically useful diene due to its high reactivity in the Diels-Alder reaction with electron-deficient alkenes to give oxygen-functionalyzed cyclohexenes and substituted cyclohexenones, which are important building blocks for the total synthesis of natural products. However, the development of catalytic enantioselective versions of Diels-Alder reactions using Danishefsky type dienes with electron-deficient alkenes has been difficult because of the instability of the dienes under Lewis acidic conditions. Only highly reactive CO and CN double bonds are employed in a hetero-Diels-Alder reaction which proceeds under catalysis of chiral Lewis acids. We have developed a new chiral ligand, BINAMIDE, which is easily prepared from 1,1'-binaphtyl-2,2'-diamine by acylation. The highly diastereo- and enantioselective Diels-Alder reaction of Danishefsky type dienes with electron-deficient alkenes in the presence of an Yb(III)-BINAMIDE complex has been developed. The reaction proceeded in an exoselective mode and gave chiral highly functionalized cyclohexene derivatives in good yields. 相似文献
4.
Ruzziconi R Ricci G Gioiello A Couthon-Gourvès H Gourvès JP 《The Journal of organic chemistry》2003,68(3):736-742
Tetraethyl vinylidenebis(phosphonate) (VBP) reacts smoothly with substituted 1,3-dienes at 90-110 degrees C without solvent to give the corresponding cyclohex-3-ene-1,1-bis(phosphonates) in good yields (60-85%). With nonsymmetrically substituted dienes, mixtures of regioisomers are obtained, the regioisomeric ratio being exclusively controlled by electronic effects. Danishefsky's diene allows tetraethyl 4-oxocyclohex-2-ene-1,1-bis(phosphonate) to be obtained in an 81% overall yield after the acid-catalyzed hydrolysis of the Diels-Alder cycloadduct. With 2,3-dimethoxy-1,3-butadiene, a mixture of regioisomeric dimethoxycyclohexene-1,1-bis(phosphonates) is formed by the VBP-catalyzed isomerization of the normal Diels-Alder cycloadduct. The mixture converges into tetraethyl 3,4-dimethoxycyclohex-2-ene-1,1-bis(phosphonate) at prolonged reaction times. 相似文献
5.
Franziska Bendrath Zharylkasyn A. Abilov Abiodun Falodun Martin Hein Alexander Villinger Peter Langer 《Helvetica chimica acta》2013,96(12):2185-2190
5‐(2‐Cyanoethyl)‐1,1′‐biphenyl‐2‐carboxylates were prepared by regioselective formal [3+3] cyclocondensations of 1,3‐bis[(trimethylsilyl)oxy]buta‐1,3‐dienes. 相似文献
6.
Fuchibe K Jyono H Fujiwara M Kudo T Yokota M Ichikawa J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(43):12175-12185
In order to synthesize polycyclic aromatic hydrocarbons with nonlinear arrangements (angular PAHs), acid‐promoted domino cyclizations of 1,1‐difluoroalk‐1‐enes and 1,1‐difluoroalka‐1,3‐dienes were studied. 1,1‐Difluoroalkenes, each bearing two aryl substituents, were regioselectively protonated with FSO3H?SbF5 to generate fluorine‐stabilized carbocations, which readily underwent domino Friedel–Crafts‐type cyclizations to give carbocycles based on 6/n/m/6 ring systems (n,m=5–7) in good to high yields. Protonation of 1,1‐difluoroalka‐1,3‐dienes took place at their electron‐rich methylene (CH2) carbon atoms in the presence of milder acids such as camphorsulfonic acid and trifluoromethanesulfonic acid. Domino cyclizations of the resulting fluorine‐stabilized allylic carbocations afford carbocycles based on 6/6/6/6 or 6/6/5/6 ring systems in high yields. 相似文献
7.
[reaction: see text] Pd(PPh3)4-catalyzed isomerization of MCPs 1 in acetic acid proceeds smoothly at 80 degrees C in toluene to give the corresponding 1-substituted or 1,1-disubstituted dienes 2 in good to excellent yields under mild conditions. The plausible mechanism has been disclosed on the basis of a deuterium-labeling experiment. 相似文献
8.
Kliman LT Mlynarski SN Ferris GE Morken JP 《Angewandte Chemie (International ed. in English)》2012,51(2):521-524
More with boron: The development of catalytic enantioselective 1,2-diboration of 1,3-dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1-disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized homoallylic alcohol products. 相似文献
9.
Unusual Formal [1+4] Annulation through Tandem P(NMe2)3‐Mediated Cyclopropanation/Base‐Catalyzed Cyclopropane Rearrangement: Facile Syntheses of Cyclopentenimines and Cyclopentenones
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Dr. Rong Zhou Kai Zhang Ling Han Yusong Chen Prof. Dr. Ruifeng Li Prof. Dr. Zhengjie He 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(17):5883-5887
An unusual formal [1+4] annulation of α‐dicarbonyl compounds with 1,1‐dicyano‐1,3‐dienes has been realized, leading to facile syntheses of cyclopentenimines and cyclopentenones in a unique manner. Mechanistic investigation implies that this reaction takes place through a P(NMe2)3‐mediated cyclopropanation followed by a base‐catalyzed cyclopropane rearrangement. It therefore represents an unprecedented [1+4] annulation mode involving Kukhtin–Ramirez adducts. 相似文献
10.
Silke Erfle Sebastian Reimann Alina Bunescu Zharylkasyn A. Abilov Anke Spannenberg Peter Langer 《Helvetica chimica acta》2012,95(6):1037-1047
The TiCl4‐mediated [3+3] cyclocondensation of various 1,3‐bis(trimethylsilyloxy)buta‐1,3‐dienes with 1‐chloro‐1,1‐difluoro‐4‐(trimethylsilyloxy)pent‐3‐en‐2‐one provides a regioselective access to novel 6‐(chlorodifluoromethyl)salicylates (=6‐(chlorodifluoromethyl)‐2‐hydroxybenzoates) with very good regioselectivity. For selected products, it was demonstrated that the CF2Cl group can be transformed to CF2H and CF2(Allyl) by free‐radical reactions. 相似文献
11.
Fujita R Oikawa K Yoshisuji T Okuyama Y Nakano H Matsuzaki H 《Chemical & pharmaceutical bulletin》2003,51(3):295-300
Cycloadditions of 1,3-butadiene derivatives having an electron-rich group at the 1-position with 4- or 3-substituted 2(1H)-quinolones were carried out to give the richly functionalized phenanthridines under both atmospheric and high pressure conditions. Furthermore, the reactivity of 4- or 3-substituted 2(1H)-quinolones acting as a dienophile with 1-substituted dienes was examined using MO calculation. 相似文献
12.
[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
13.
One-pot synthesis of trisubstituted conjugated dienes via sequential Suzuki-Miyaura cross-coupling with alkenyl- and alkyltrifluoroborates 总被引:1,自引:0,他引:1
The sequential, stereoselective disubstitution of 1,1-dibromoalkenes using a variety of alkenyltrifluoroborates followed by alkyltrifluoroborates in the presence of Pd(PPh3)4 is described. This synthetic method proceeds smoothly in one pot under mild reaction conditions to provide the corresponding trisubstituted, conjugated dienes in excellent yield. Moreover, the method is operationally very simple because the organotrifluoroborates are stable in air, and the byproducts are innocuous inorganic salts. 相似文献
14.
2‐Ethoxycarbonyl‐substituted 1,3‐dienes and 1,3‐enynes can be stereoselectively synthesized in one pot under mild conditions, in good yields, by the palladium‐catalyzed hydrostannylation of alkynyl esters, followed by Stille coupling with alkenyl or alkynyl halides, respectively. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
15.
The C-H bond of a terminal alkyne adds to a carbon-carbon double bond of 1,3-dienes, styrenes, and norbornene at room temperature in the presence of a nickel catalyst in regio- and stereoselective manners. Reaction of triisopropylsilylacetylene with 1-substituted 1,3-butadiene derivatives afforded hydroalkynylation products via introduction of a hydrogen atom and a triisopropylsilylethynyl group to 4- and 3-positions of the dienes, respectively. Likewise, 1-triisopropylsiloxy-1,3-butadiene, 1,3-pentadiene, 1-cyclohexen-1-yl-1,3-butadiene, and 1,3-cyclohexadiene underwent the hydroalkynylation reaction, giving the corresponding 1,4-enyne derivatives in good yields at room temperature. Reaction of p-substituted styrene with triisopropylsilylacetylene also proceeded in the presence of the nickel catalyst, giving the branched hydroalkynylation products in good yields. Norbornene gave a exo-addition product in good yield under the same reaction conditions. 相似文献
16.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(12):3249-3253
An efficient approach for organoselenium‐catalyzed regioselective C−H pyridination of 1,3‐dienes to form pyridinium salts has been developed. This method was also successfully applied to direct C−H pyridination of alkenes. Fluoropyridinium reagents, or initially loaded pyridine derivatives, acted as pyridine sources in the pyridination reactions. The obtained pyridinium salts could be further converted under different conditions. This work is the first example of catalytic C‐2 direct C−H functionalization of 1,3‐dienes and the first case of organoselenium‐catalyzed C−H pyridination. 相似文献
17.
Alajarín M Cabrera J Pastor A Sánchez-Andrada P Bautista D 《The Journal of organic chemistry》2007,72(6):2097-2105
Somewhat unexpectedly, the computed highest occupied molecular orbital (HOMO) energies of some 4-alkenylthiazoles afforded values close to those calculated for the Danishefsky-Kitahara and Rawal dienes. In fact, 4-alkenylthiazoles behave as all-carbon dienes in Diels-Alder reactions with the participation of the formal C-C double bond of the thiazole ring and the side-chain double bond. The reactions with N-substituted maleimides, maleic anhydride, and naphthoquinone take place with high levels of stereocontrol to give the corresponding endo-cycloadducts in good to excellent yields. Depending on the dienophile, the cycloadduct further transforms under the reaction conditions through either a 1,3-hydrogen shift, dehydrogenation, or an ene reaction or Michael addition with another molecule of dienophile. These unprecedented results open new synthetic perspectives for the functionalization of the thiazole ring. 相似文献
18.
A comparative study of the Diels-Alder reaction have been carried out for three types of cyclic dienes: cyclopentadiene (CPD), hexachlorocyclopentadiene (HCP), and tetrachloro-1,2-benzoquinone (TCBQ) with dienophiles of five types: monosubstituted acetylenes (propargyl alcohol and its esters), conjugated amines (allyl acetylene, allyl ethynyldimethylcarbonol and its esters), conjugated dienes (2-methylhexadiene-3,5-ol-2 and its esters, 1-ethoxy- and 1-ethoxycarbonylbutadiene-1,3), and conjugated trienes (hexatriene-1,3,5 and 5-methylhexatriene-1,3,5).It was found that conjugated trienes react with dienes of all types under mild conditions and give only the monoadducts through the terminal vinyl or ethynyl group. 相似文献
19.
Roger Arnaud Pierre-Yves Chavant Fatiha Hagoug Nadia Pelloux-leon Jean-Louis Ripoll Yannick Vallee 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):319-320
Abstract i) When generated under FVT conditions α-imino-thioaldehydes undergo a cyclization to dihydro-1,3-thiazoles. ii) Thienium cations, generated during a Pummerer reaction, can be trapped with dienes. 相似文献
20.
Knoevenagel-type condensation of 1,3-bis(phenylsulfonyl)propene with aldehydes provided electron-deficient dienes, 1,3-bis(phenylsulfonyl)butadiene derivatives, and one of these dienes, 4-[3,4-(methylenedioxy)]phenyl derivative was applied to Michael-type addition with enamines to form six-membered ring systems. 相似文献