共查询到20条相似文献,搜索用时 46 毫秒
1.
Masanori Yoshida 《Journal of fluorine chemistry》2004,125(4):527-529
(Z)-β-Fluoro-α,β-unsaturated esters were stereoselectively synthesized from (Z)-2-fluoro-1-alkenyliodonium salts by the Pd-catalyzed methoxycarbonylation reaction. The reaction proceeded at room temperature and various functional groups on the substrate can tolerate the reaction conditions. 相似文献
2.
Qibo Liu 《Journal of fluorine chemistry》2011,132(2):78-87
(Z)-HFCCFZnI was stereoselectively synthesized from activated zinc dust and (Z)-HFCCFI that was synthesized from chlorotrifluoroethene in a sequential manner. Compared to (E)-HFCCFZnI, (Z)-HFCCFZnI was more challenging to prepare in terms of sluggish metallation and formation of by-products, and underwent slower and incomplete Negishi coupling with aryl iodides. In a modification of Negishi coupling, (E)-α,β-difluorostyrenes were stereospecifically prepared in good to excellent yields under mild conditions from aryl iodides and (Z)-HFCCFZnI with the co-catalysis of Pd(PPh3)4/Cu(I)Br. Experimental investigation and mechanistic rationalization suggested that Cu(I)Br would be a scavenger of free ligands for the facilitation of Pd(PPh3)2 formation, and a supplier of ligand for the metathesis process. Alternatively, (Z)-HFCCFSnBu3 and aryl iodides with an electron-withdrawing group underwent Stille-Liebiskind coupling to afford (E)-α,β-difluorostyrenes. 相似文献
3.
The (Z)-isomer of a phytotoxic nonenolide, (6S,7R,9R)-6,7-dihydroxy-9-propylnon-4-eno-9-lactone isolated from Phomopsis sp. HCCB03520 and its C-6 epimer have been synthesized through a common route starting from butyraldehyde. The synthesis involves enantioselective Maruoka allylation, Sharpless asymmetric epoxidation and intramolecular ring closing metathesis as the important steps. 相似文献
4.
Various (Z)-chalcone derivatives were easily synthesized in a stereoselective manner from 1,3-diaryl-2-propynyl silyl ethers by a catalytic reaction using potassium tert-butoxide under very mild conditions after acid treatment. 相似文献
5.
François-Hugues PoréeAlexandre Clavel Jean-François Betzer Ange PancraziJanick Ardisson 《Tetrahedron letters》2003,44(40):7553-7556
A (Z)-vinyl (N,N-diisopropyl)carbamate treated with Grignard reagents, under Wenkert Nickel-catalysed conditions, gave access to several substituted (Z)-alkenyl derivatives. These Nickel-catalysed reactions, carried out with vinyl-, phenyl-, p-methoxyphenyl-, trimethylsilylmethylmagnesium bromide and benzylmagnesium chloride, led to the corresponding (Z)-alkenyl derivatives in good yields and high stereoselectivities. 相似文献
6.
Biotransformation of (+)-(1R,2S)-fenchol by the larvae of Spodoptera litura was carried out. Substrate was converted to three new terpenoids, (+)-(1R,2S)-10-hydroxyfenchol, (+)-(1R,2R,3S)-8-hydroxyfenchol and (−)-(1S,2S,6S)-6-exo-hydroxyfenchol, and one known terpenoid, (−)-(1R,2R,3R)-9-hydroxyfenchol. These structures were established by NMR, IR, specific rotation and mass spectral studies. 相似文献
7.
Jocelyn G. Millar Mark Hoddle J. Stephen McElfresh Yunfan Zou Christina Hoddle 《Tetrahedron letters》2008,49(33):4820-4823
The highly unsaturated aldehyde (9Z)-9,13-tetradecadien-11-ynal and the corresponding alcohol were identified as possible sex pheromone components of the avocado seed moth, Stenoma catenifer. The aldehyde as a single component attracted more male moths than caged virgin female moths, and addition of the analogous alcohol and/or acetate decreased attraction. A stereospecific synthesis of the pheromone is described. 相似文献
8.
Biswanath Das Anjoy Majhi Joydeep Banerjee Nikhil Chowdhury Katta Venkateswarlu 《Tetrahedron letters》2005,46(46):7913-7915
A highly efficient synthesis of (Z)- and (E)-allyl iodides has been accomplished by treatment of Baylis-Hillman adducts with iodine and triphenylphosphine in methylene chloride at room temperature. The method is associated with mild reaction conditions, high yields and excellent stereoselectivity. 相似文献
9.
Kazuhiro Yoshizawa 《Tetrahedron》2007,63(27):6259-6286
Siloxyallenes proved to be a useful functional intermediate in the preparation of (Z)-β-branched Morita-Baylis-Hillman type adducts by the reaction of aldehydes with silylacetylenes or siloxypropynes. Various (Z)-chalcones were stereoselectively synthesized from siloxypropynes via siloxyallenes. 相似文献
10.
We report a highly efficient method for the synthesis of (Z)-3-ylidenephthalides via intramolecular cyclization of readily available 2-acyl-benzoic acids mediated by TSTU at room temperature. Using this method, diversely substituted (Z)-3-ylidenephthalides have been generated in good to excellent yields. The application of the method is highlighted by gram-scale preparation of the antiplatelet drug n-butylphthalide. 相似文献
11.
Carlos E.D. NazarioAmanda S. Santana Cristiane Y. KawasokoCarlos A. Carollo Gabriela R. HurtadoLuiz H. Viana Sandro L. BarbosaPalimécio G. Guerrero Jr. Francisco A. MarquesVânia B. Dabdoub Miguel J. DabdoubAdriano C.M. Baroni 《Tetrahedron letters》2011,52(32):4177-4181
Sonogashira cross-coupling reactions involving (E)-iodo vinyl stannanes and terminal acetylenes were carried out in the presence of Pd(PPh3)4, CuI and several amines, affording (Z)-tributylstannyl enynes in moderate to good yields (62-91%). Utilizing the catalytic system containing Pd(PPh3)4 (5%), CuI (10%), and TBAOH (40% in aqueous media) as activator, better yields (72-91%) and lower reaction times were achieved. 相似文献
12.
(Z)-1-Bromo-1-alkenes were stereoselectively prepared in high yields in a short reaction time by microwave irradiation of the corresponding anti-2,3-dibromoalkanoic acids in a Et3N/DMF system. A one-pot synthesis of terminal alkynes and enynes from 2,3-dibromoalkanoic acids were also developed by microwave-induced reaction. 相似文献
13.
A stereoselective method has been developed for the synthesis of (Z)- and (E)-allyl iodides from Baylis-Hillman adducts using polymethylhydrosiloxane (PMHS) and iodine in chloroform at room temperature. In addition, the reagent system has been utilized for the iodination of benzylic alcohols selectively. 相似文献
14.
Qibo Liu 《Journal of fluorine chemistry》2009,130(10):922-925
(E)-(1,2-Difluoro-1,2-ethenediyl)bis[tributylstannane], 3, readily undergoes a Pd(PPh3)4/CuI-catalyzed cross-coupling reaction with iodotrifluoroethene to yield (E)-octafluoro-1,3,5-hexatriene, 4, in high isomeric purity. (1Z,3E,5Z)-(1,2,3,4,5,6-Hexafluoro-1,3,5-hexenetriyl)bis[tributylstannane], 7, was sequentially prepared from (1Z,3E,5Z)-(1,2,3,4,5,6-hexafluoro-1,3,5-hexenetriyl)bis[triethylsilane], 5, which was prepared via a Pd(PPh3)4/CuI-catalyzed cross-coupling reaction of 3 with (E)-1,2-difluoro-1-iodo-2-triethylsilylethene, 6. Pd(PPh3)4/CuI cross-coupling of 7 with iodotrifluoroethene gave (3E,5E,7E)-dodecafluoro-1,3,5,7,9-decapentaene, 8. 相似文献
15.
Feijie Song 《Journal of organometallic chemistry》2009,694(4):502-495
A facile approach for the syntheses of spirocyclic butenolides through cascade cyclization/oxidative cleavage reactions of (Z)-enynols bearing cyclic substituents at the C-1 position catalyzed by gold under dioxygen atmosphere has been developed. A variety of substituted butenolides was constructed in a regioselective manner from suitably substituted (Z)-2-en-4-yn-1-ols. (Z)-Enynols substituted both at C2 and C3-position afforded the spirocyclic butenolides in moderate to good yields, C-2 unsubstituted (Z)-enynols afforded the products in moderate yields, and the C-3 unsubstituted (Z)-enynols afforded the desired products in low yields. 相似文献
16.
A Ni-catalyzed cross-coupling reaction of (Z)-5-(tert-butyldiphenylsilyl)oxy-3-bromo-1-trimethylsilyl-3-penten-1-yne (1) with alkyl Grignard reagent gives (Z)-3-alkyl-5-(tert-butyldiphenylsilyl)oxy-1-trimethylsilyl-3-penten-1-ynes (2) stereospecifically in good yields. The (Z)-enyne 2a is transformed in four steps to (Z)-3-methyl-5-silyloxy-3-pentenal (3), which is coupled with ketophosphonate 4 to give enone 13. The η-hydroxyallyl methanesulfonate derived from 13 is cyclized to 3,6-dihydro[2H]pyran by an intramolecular SN2′ reaction stereoselectively, furnishing a C17-C27 carbon unit of (−)-laulimalide. 相似文献
17.
Yunfan Zou 《Tetrahedron letters》2010,51(9):1336-1337
The terminal dienyne of (9Z)-9,13-tetradecadien-11-ynal, the sex pheromone of the avocado seed moth, Stenoma catenifer, was constructed by coupling a vinyl iodide precursor with commercially available 1-buten-3-yne with Pd catalysis, resulting in a short and efficient synthesis of the pheromone. 相似文献
18.
Srinivas Reddy Dubbaka 《Tetrahedron》2005,61(6):1523-1530
2-Methylprop-2-ene-1-sulfonyl fluorides can be easily prepared via the ene reaction of methallylsilanes and SO2. In the presence of a base, aldehydes and 2-methylprop-2-ene-1-sulfonyl fluorides give 1,3-(E) and (Z)-dienes. Their (Z)→(E) isomerization by classical means fails or leads to their polymerization. It is shown that SO2 can isomerize 1-aryl-3-methyl-1,3-dienes at low temperature, without formation of sulfolenes (cheletropic addition/elimination). Preliminary mechanistic studies suggest that SO2 adds to 1,3-dienes forming 1,4-diradical intermediates that are responsible for the (Z)→(E) isomerizations. 相似文献
19.
Yasser M.A. MohamedTrond Vidar Hansen 《Tetrahedron letters》2011,52(10):1057-1059
The first total synthesis of methyl (5Z,8Z,10E,12E,14Z)-eicosapentaenoate has been achieved in seven steps and in 16% overall yield. The synthesis confirmed the assigned structure of this polyunsaturated natural product. 相似文献
20.
Biswanath Das Kongara Damodar Nisith Bhunia Boddu Shashikanth 《Tetrahedron letters》2009,50(18):2072-5609
Appel agents (PPh3/CBr4) have been utilized for high-yielding stereoselective synthesis of (Z)- and (E)-allyl bromides from Baylis-Hillman adducts at room temperature. The method has been applied for the synthesis of naturally occurring bioactive fatty acid amides, semiplenamides C and E. 相似文献