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1.
Nobuya Katagiri Masayuki Sato Toshihiko Naito Makoto Muto Toshiyuki Sakamoto Satoshi Saikawa Chikara Kaneko 《Tetrahedron letters》1984,25(49):5665-5668
The title compound, a synthetic equivalent of 4-(2-oxoethyl)-azetidin-2-one, has been synthesized as a stable crystalline solid either from 4-(-butyldimethylsilyloxy)- or 4-benzyloxy-2-pyridone photopyridone formation, catalytic hydrogenation, and deblocking of the protecting group. 相似文献
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(E)- and (Z)-1-benzenesulfonyl-4-trimethylsilyl-2-butenes (E/Z=9), prepared from 4-trimethylsilyl-1-buten-3-ol, -butyllithium and benzenesulfenyl chloride and oxidation of the intermediate (E)- and (Z)-1-benzenesulfinyl-4-trimethylsilyl-2-butenes with hydrogen peroxide, react with -butyllithium and then primary halides to give 4-benzenesulfonyl-1-trimethylsilyl-2-alkenes which are rapidly 1,4-debenzenesulfonyltrimethylsilated to (E)-1,3-alkadienes by tetra--butylammonium fluoride at O°C. 相似文献
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Douglas O. Spry 《Tetrahedron letters》1980,21(14):1293-1296
Preparation of acetylenic-S(1)-C(2)-secocephems from the reaction of Grignard reagents on -α-vinylhalo sulfoxides. 相似文献
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Françoise Barrière Jean-Claude Barrière Derek H.R. Barton Jeanine Cleophax Alice Gateau-Olesker Stephan D. Géro Fatemeh Tadj 《Tetrahedron letters》1985,26(26):3119-3120
The 1-cyano-1-thiophenylcyclopentone derivative , obtained from (R,R)-(+)-tartaric acid, has been converted into a number of derivatives including the important -(3S,4S)-dibenzyloxycyclopentanone in 45% overall yield. 相似文献
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Kōichi Mikami Toshihiko Maeda Naoyuki Kishi Takeshi Nakai 《Tetrahedron letters》1984,25(45):5151-5154
An enantiospecific synthesis of the title compound is described which involves the TiCl4-promoted cyclization of the chiral allylic silane having formyl group, which was obtained via the Claisen rearrangement of (, )-1-trimethylsilyl-1-buten-3-ol. 相似文献
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Takehiko Nishio Katsuhiro Katahira Akira Kato Choji Kashima Yoshimori Omote 《Tetrahedron letters》1979,20(43):4211-4212
Irradiation of N-aryl-2(1H)-pyrimidin-2-ones (-) in a mixed benzene-alcohol solution afforded the products initiated by Type I cleavage, 1-(3-alkoxycarbonylamino-2-propene)-N-arylimines (-, , and ) in 45–51% yields. 相似文献
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Thermal treatment of β-allenic esters () with alumina catalyst in aprotic solvents yielded (2E,4Z)-dienoic esters () in 57-58% yield with 91-100% stereoselectivity. 相似文献
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A stereoselectivity in an intramolecular cycloaddition of the olefinic -quinodimethanes 13 and 23 generated from the thermolysis of optically active 4β-[2-(4-methoxybenzocyclobutenyl)ethyl] -5α-methoxymethyl-3-phenyl-thio-methylenefuran-2-ones 12 and 22, respectively, is studied and a stereoselective synthesis of (+)--4,5-( 4-methoxybenzo) -1β,7aβ-(2α-methoxymethyl-5-oxofuro)hydrindane 1 is also described. 相似文献
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The cycloaddition of α,β-epoxyaldehydes or ketones () with the ketene acetal MeHC=C(OMe)2 () gives epoxyoxetanes () in high yields. Without isolation they can be transformed into 4-hydroxy-5-(1-hydroxyalkyl)-γ-butyrolactones () via the epoxy esters and trihydroxy esters (). The lactones appear to be valuable precursors for the synthesis of 5-(1-hydroxyalkyl)-3-methyl-2-5H-furanones () and 3-methyl-5-ylidene-2-5H-furanones () 相似文献
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Mikio Hori Tadashi Kataoka Hiroshi Shimizu Akihiko Tomoto 《Tetrahedron letters》1981,22(37):3629-3632
1-Benzoyl-2-methy1-3,4-dihydro-2-thianaphthalene () underwent novel intermolecular 1,4-rearrangement in refluxing toluene to give an enol ether , while rearrangement of 2-phenyl derivative proceeded intramolecularly in refluxing xylene to afford a 1,4-rearranged enol ether . On the other hand, ylides were refluxed in alcohols to afford some ring-opened products . 相似文献
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The formation of a thermally unstable (4+2)-cycloadduct, a 4H-1,2-oxazine 2-oxide derivative (), from the reaction of 1-nitrocyclopentene with 1-phenyl-2-(1-pyrrolidinyl)acetylene has been proven by the structure elucidation of isoxazole derivative which results from thermal rearrangement and by the structure determination of the 1,3-dipolar adducts of with electron-deficient acetylenes. 相似文献
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Masatoshi Asami 《Tetrahedron letters》1985,26(47):5803-5806
cis-4-t-Butyldimethylsiloxy-2-cyclopenten-1-ol and cis-4-tetrahydropyranyloxy-2-cyclopenten-1-ol were obtained with high enantiomeric excesses (ee) by the reaction of cis-3,4-epoxycyclopentan-1-ol derivatives with chiral lithium amide. An application to the syntheses of both ()- and ()-4-hydroxy-2-cyclopentenone was demonstrated. 相似文献
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A new and convenient synthesis of 2-isopropylfuro-(2,3-b)quinolines () from 3-(3-methylbut-1-enyl)-2-quinolones () is described. A neat synthesis of the alkaloids (±)-lunacrine (), (±)-lunasine () and (±)-demethoxylunacrine () is also reported. 相似文献
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1-Ehtoxycarbonyl-1, 2-dihydroquinoline-2-phosphonates () were treated with n-butyllithium followed by alkyl halides to afford the corresponding 4-alkylated phosphonates () with complete regioselectivity in 67–97% yields. The phosphonates () were converted to 4-alkylquinolines () in ca. 50% yields by treatment with sodium iodide in HMPA or by alkaline hydrolysis in aqueous ethanol. 相似文献
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The major precursor to the maytansinoids containing 4 non-racemic chiral centers has been prepared in gram quantities, suitable for further synthesis. The route to (+)- was accomplished in 13 steps including several highly stereocontrolled reactions which precluded resolutions or separations. 相似文献