共查询到20条相似文献,搜索用时 15 毫秒
1.
Methods are described for the stereospecific conversion of hydrindenone 3 either to the corresponding fused or fused hydrindanone (1 or 2, respectively.) 相似文献
2.
Complexes of the type L2PdCl2 (L = CH3,CN, CH3CH2CN, PhCN) in benzene or chloroform act as homogeneous catalysts in the room temperature to isomerization of ethylchrysanthemate and chrysanthemic acid. 相似文献
3.
A novel olefin metathesis sequence permits ready access to functionalised , , -tricyclo [6.3.0.02,6] undecane based bis-enones. These bis-enones have been shown to undergo cage cyclisation in sunlight with remarkable ease and efficiency. 相似文献
4.
Roshantha A.S. Chandraratna Robert R. Birge William H. Okamura 《Tetrahedron letters》1984,25(10):1007-1010
The electronic absorption spectra of the four new 12---locked retinals (1a–1d) bearing 7-, 11- double bond geometries are described and compared with those of analogous 7-, 11--geometries (1e–1h) and parent retinals (2a-h). 相似文献
5.
Intramolecular DIELS-ALDER reactions of requisite trienes led to -1-decalones, an endo intermediate state. 相似文献
6.
The 6-hydroperoxy-1,4-cyclooctadiene (), which is formed in the photosensitized oxygenation of 1,5-cyclooctadiene (), affords on further singlet oxygenation 5,8-dihydroperoxy-1,3-cyclooctadiene (), which via triphenylphosphine reduction leads to -5,8-dihydroxy-1,3-cyclooctadiene () and subsequent pyridinium chlorochromate oxidation to 1,3-cyclooctadien-5,8-dione (). 相似文献
7.
For 12-- locked retinal analogues, thermal equilibria are established between 11-, 13--1c and 13--2c and between 9-, 11-, 13--1d and 9-, 13--2d; a photoisomerization occurs to transform 2c to --2a and 2d to 9--2b 相似文献
8.
A stereospecific route to -2,2-dimethyl-3-alkenyl-cyclopropanecarboxylic Acids is illustrated by a total synthesis of (±)--Chrysanthemic Acid (11). The key step consists of an alicyclic Claisen rearrangement of -silyl enolates derived from appropriately substituted ()-4-hexen-6-olides [e.g.(9)]. 相似文献
9.
Masao Tokuda Yasufumi Yamada Toshiya Takagi Hiroshi Suginome Akio Furusaki 《Tetrahedron letters》1985,26(49):6085-6088
Neutral aminyl radicals generated by anodic oxidation of lithium alkenylamides 2 undergo a stereoselective cyclization to give -1-methyl-2,5-disubstituted pyrrolidines 4. Their stereochemistry was confirmed by a comparison with -1,2-dimethyl-5-phenylpyrrolidine, the structure of which was established by X-ray crystallographic analysis of its quarternary ammonium bromide 6. 相似文献
10.
The 1H and 13C nmr spectra of , -9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid, 3, in DMSO-d6 or alkaline D2O, clearly show that it exists in a --conformation with carboxyl groups, thus being the first case of - preference of a bicyclo[3.3.1] nonan-9-one due to the presence of ,-2,4- substituents. 相似文献
11.
M.V. Lakshmikantham Michael P. Cava Michael Albeck Lars Engman Patrick Carroll Jan Bergman Fred Wudl 《Tetrahedron letters》1981,22(42):4199-4200
The reaction of sodium phenylethynyltellurolate with ethereal hydrogen chloride afforded, in addition to -2,4-dibenzylidene-1,3-di telluretane, a product shown to be the title compound by an X-ray crystallographic analysis. 相似文献
12.
N-Acyl derivatives of ,-acosamine and ,-ristosamine were synthesized with high stereo selectivity utilizing intramolecular Michael addition of γ- and δ-carbomoyloxy-α,β-unsaturated esters. 相似文献
13.
Tadashi Nakata Shigeto Nagao Sachiko Takao Tadasu Tanaka Takeshi Oishi 《Tetrahedron letters》1985,26(1):73-74
(1,3,5)-1,3-Dimethyl]-2,9-dioxabicyclo[3.3.1]nonane has been stereoselectively synthesized based on a highly stereoselective method for the synthesis of 1,3--polyol. 相似文献
14.
P. Caramella F.Marinone Albini D. Vitali Nelson G. Rondan Yun-Dong Wu Timothy R. Schwartz K.N. Houk 《Tetrahedron letters》1984,25(18):1875-1878
Benzonitrile oxide cycloadds preferentially to the substituents of -3,5-di-X-cyclopentenes, where X = OMe, OAc, OCOPh, Br, Cl, and OH. Higher stereoselectivities are found for -2,5-di-X-2,5-dihydrofurans. The origins of these selectivities, and contrasts with acyclic and cyclobutene analogs, are described. 相似文献
15.
(1,5)-(-)-Karahana ether (8,8-dimethyl-2-methylene-6-oxabi-cyclo[ 3.2.1]octane) and (1,5)-(-)-karahana lactone (8,8-dimethyl-2-methylene-6-oxabicyclo [3.2.1]octan-7-one) were synthesized from ()-3-hydroxy-2,2-dimethylcyclo-hexanone. The natural karahana lactone was shown to be almost racemic (. 1.3 % e.e.). 相似文献
16.
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
17.
A general synthetic route to optically active -1,2-disubstituted cyclopropanes has been developed from the key intermediates 3 and 4. 相似文献
18.
1,3,7,9,11,12,14-Heptazapentacene-2,4,8,10 (14,3,9,12)-tetraones (mixed flavins) were prepared by the cyclization of 1,5-dihydro-8-[N-alkyl-N-(5-nitrouracil-6-yl)-amino-5-deazaflavins with Vilsmeier reagent. The mixed flavins oxidized alcohol under neutral condition in sunlight and a remarkable autorecycling was observed. 相似文献
19.
Giovanni Fronza Claudio Fuganti Piero Grasselli Giulio Marinoni 《Tetrahedron letters》1979,20(40):3883-3886
The enantiomeric alcohols () and (), obtained from (2,3) tartaric acid and, respectively, -threonine, have been used to construct the C6, enantiomeric deoxy amino sugar derivatives () and () 相似文献
20.
Hideo Kigoshi Makoto Ojika Yoshikazu Shizuri Haruki Niwa Kiyoyuki Yamada 《Tetrahedron letters》1982,23(51):5413-5414
From a red alga (10, 11)-(+)-squalene-10, 11-epoxide was isolated and its asymmetric synthesis has been achieved starting from -farnesol. 相似文献