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1.
Takashi Toda Norihiko Shimazaki Toshio Mukai Chizuko Kabuto 《Tetrahedron letters》1980,21(41):4001-4004
The structure of a minor dimer () of 1-arylcycloheptatrienylidenethylene was determined by X-ray crystallography. Dehydration of and gave novel non-benzenoid aromatics---6,12-diarylazuleno[1,2-b]azulenes ( and ), whose electronic and NMR spectral properties were reported. 相似文献
2.
Through the insertion of a carbon dioxide molecule, the oxazolidin-2-ones () and () were prepared by treataent of the salts () and () with carbonate anion on polymeric support. The hydrolysis under basic conditions of () and () afforded the erythro-3-amino-1,2-diols () and () which were fully acetylated: the 2-amino-2-deoxyerythritol derivative () was obtained in 91% yield. 相似文献
3.
Yasuo Sakai Shingo Toyotani Yoshito Tobe Yoshinobu Odaira 《Tetrahedron letters》1979,20(40):3855-3856
Oxidative decarboxylation of [n.2.2]propellane carboxylic acids (-) with lead tetraacetate gave the bicyclic acetates (, ) having a bridgehead double bond and/or the tricyclic acetates (, ) in good yields. Vapor phase thermolysis of or afforded the bridgehead olefin or quantatively. 相似文献
4.
N,N-Dimethylformamide () and N,N-dimethylpivalamide () react with carbonyl chloride isocyanate () in the presence of antimony pentachloride to afford the amino substituted 1-oxa-3-azabutatrienium hexachloroantimonates ,. An X-ray diffraction analysis of confirms the proposed structure. The heterocumulenes , react with aldehydes, ketones and tertiary carboxamides to give the amino substituted 2-azaallenium salts - in high yields. 相似文献
5.
Jack E. Baldwin Robert M. Adlington Bernard J. Rawlings Richard H. Jones 《Tetrahedron letters》1985,26(4):485-488
Practical procedures for the resolution of racemic modification of (1, 2)-and (1, 2)-1-amino-2-ethylcyclopropane-1-carboxylic acid ,,(1, 2)- and (1, 2)-1-amino-2-methylcyclopropane-1-carboxylic acid ,, and (1, 2)- and (1, 2)-1-amino-2-methylcyclopropane-1-carboxylic acid , are described; the structures as ,, and were confirmed by X-ray-crystallographic methods. 相似文献
6.
The cationic cyclization of the carbinol (Z) occurred stereoselectively and resulted in a mixture of the hydrindane and the octalin , both with configuration of side chain and angular methyl group. Cyclization of (E) yielded in and , both with -configuration. The structure of , was proved by transformation to the diketones ,. 相似文献
7.
The reaction of dichlorocarbene with 1,2-bismethylenecycloheptane yields, besides the 1,2-addition product , the 1,4-addition product in a ration 99:1. 相似文献
8.
The α-anions of 2-substituted 1,3-dioxolan-4-ones derived from chiral mandelic and lactic acid (, ; ; , ) were alkylated with high stereoselectivity. The products formed were hydrolysed to α-hydroxy acids with 65–85% e.e. ((S)(+)-,,, (R)(–)-). 相似文献
9.
(±)-Isoagatholactone and (±)-12α-hydroxyspongia-13(16),14-dien , a fundamental skeleton of spongiadiol and its congeners, have been synthesized from (±)-labda-8(20),13-dien-15-oic acid . 相似文献
10.
A short synthesis of a functionalized gibbane is described. The key-step involves the intramolecular Diels-Alder reaction of furan-diene , leading to a 3:1 ration of two diastereoisomers, tentatively identified as and . The precursor is obtained form-m-methoxybenzoic acid in 7 steps. 相似文献
11.
In a synthetic approach to macrostomine , both side chains of the isoquinoline nucleus are attached by high yield carbon carbon bond formation with lithiated nitrosamines ( → , → ). 相似文献
12.
Herbert L. Holland David B. MacLean Russell G.A. Rodrigo Richard F.H. Manske 《Tetrahedron letters》1975,16(49):4323-4326
The reduction product of dehydrocordrastine, , with di-isobutylaluminum hydride spontaneously rearranged to the spirobenzylisoquinolines and , analogous to the alkaloids sibiricine (), corydaine (), and yenhusomidine (). 相似文献
13.
2,3-dihydroazete 1-oxide reacts at room temperature with base, acid and lead tetraacetate to give the 5-hydroxyisoxazolidines and , the 6H-1,2-oxazin-6-one and the N-acetoxy β-lactam , respectively; the reaction with lead tetraacetate represents a simple one-step conversion of a 4-membered cyclic nitrone into a β-lactam. 相似文献
14.
The synthesis of 3-acetylcyclohexanones , , has been realized by conjugate addition of lithiated cyanohydrin ether to 2-cyclohexenones , , in THF-HMPA, even if 3-substituted. 3-benzoylcyclohexanones , , are obtained from and , , in THF with excellent yields. 相似文献
15.
《Tetrahedron letters》1986,27(19):2117-2120
Highly stereoselective addition of Grignard reagents to chiral open-chain α,-ketoacetals (,) has been attained. Application of the reaction to syntheses of the key intermediates (,) for (R)- and (S)-mevalolactone is also described. 相似文献
16.
Enamino-thiones 1 prepared from the corresponding enaminones by thiation with Lawesson's Reagent, were allowed to react with 2-chloroacrylonitrile and dimethyl acetylenedicarboxylate giving dihydro-2-thiopyrans, 2, and 4-thipyrans, 3, respectively. The reaction of 1a with ethyl propiolate at room temperature afforded 4-thipyrans, 4a, which on standing rearranged to 2-thiopyran, 5a(1, 3 amide shift). The reaction of 1b with ethyl propiolate produced 4b and 5b. Some of the 13C NMR data are reported. 相似文献
17.
11-Deoxyanthracyclinone precursors and have been prepared regiospecifically by the reaction of bromojuglone methyl ethers and with vinylketene acetal , prepared from the Hagemann's ester ketal . 相似文献
18.
Acid-catalysed ring opening of the spirodienones () and () using p-toluene-sulphonic acid affords the styrène derivatives () and (), while treatment with acetic anhydride/H2SO4 affords the furan derivatives () and (). 相似文献
19.
Under both static and flow thermolysis conditions, several compounds with an “aspidosperma” framework rearranged to “vinca” derivatives. Thus (-)1,2-dehydroaspidospermidine () rearranged to (-) gave vincane . Compound rearranged to vincamine () and 16-epi vincamine () under either condition ; increasing the temperature resulted in formation of apovincamine () (pyrolysis) or vincamone thermolysis). 相似文献
20.
3-(t-Butoxycarbonyl)-2-(trifluoromethyl)imidazo[1,2-]-pyridine, prepared from trifluoroacetonitrile and pyridinium t-butoxycarbonylmethylide, reacts smoothly with trifluoroacetic acid to provide 2-(trifluoromethyl)imidazo[1,2-]pyridine-3-carboxylic acid, which gives 2-(trifluoromethyl)imidazo[1,2-]-pyridine when heated. 3-Cyano-2-(trifluoromethyl)imidazo[1,2-]pyridine can be obtained treatment of trifluoroacetonitrile with pyridinium cyanomethylide, which is sufficiently reactive to effect nucleophilic displacement of fluorine from pentafluoropyridine under mild conditions [→pyridinium cyano(tetrafluoro-4-pyridyl)methylide]. 相似文献