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1.
The structure of a new natural compound has been established as 5-isopropylbicyclo[3.1.0]hex-3-en-2-one, which has been called lebaikon. Two bicyclic monoterpenoids (2-formyl-5-isopropylbicyclo[3.1.0]hex-2-ene and 4-isopropyl-1-methylbicyclo[3.1.0]hexan-2-one) have been detected in natural materials for the first time. 相似文献
2.
Giorgio Adembri Donato Donati Lucia R. Lampariello Mirella Scotton Alessandro Sega 《Tetrahedron letters》1984,25(52):6055-6058
The stereochemistry of (1a,4β,5a)-1,5-diacetyl-4-hydroxy-4-methylbicyclo[3.1.0]hexan-2-one, the main cycloadduct of 2,3-diacetyl-4-hydroxy-4-methylcyclopent-2-en-1-one and diazomethane, was unambiguously established from a single crystal X-ray analysis. 相似文献
3.
David A. Lightner Chwang Siek Pak B.Vincent Crist Stephen L. Rodgers John W. Givens 《Tetrahedron》1985,41(19):4321-4330
(lS,5S)-exo-2(R)-Methylbicyclo[3.1.0]hexan-3-one () and (lS,5S)-endo-2(S)-methylbicyclo[3.1.0]hexan-3-one (2) were synthesized and their circular dichroism (CD) spectra run. Conformational analysis based on molecular mechanics calculations and Karplus equation analyses of vicinal H¦H NMR coupling constants indicate boat-like sofa conformations for both and , with very little ring distortion from the symmetry of the parent bicyclo[3.1.0]hexan-3-one. The lone dissymmetric ψ-axial and ψ-equatorial methyl groups of and , respectively, are both octant consignate. The natural product analogs of and , (?)-3-isothujone () and (+)-3-thujone () were prepared and examined similarly. Their α-methyl perturbers dominate the CD n-π★ Cotton effects. 相似文献
4.
The structure of a new natural compound has been established as 5-isopropylbicyclo[3.1.0]hex-3-en-2-one, which has been called lebaikon. Two bicyclic monoterpenoids (2-formyl-5-isopropylbicyclo[3.1.0]hex-2-ene and 4-isopropyl-1-methylbicyclo[3.1.0]hexan-2-one) have been detected in natural materials for the first time.Tomsk State Medical Institute. Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 627–629, September–October, 1990. 相似文献
5.
Optically pure sulfinylfuranones undergo oxidation at sulfur followed by a totally stereoselective epoxidation at the electron deficient double bond by treatment with MCPBA at room temperature to afford, in good yields, enantiomerically pure 4-ethoxy-5-alkyl-1-p-tolylsulfonyl-3,6-dioxabicyclo[3.1.0]hexan-2-ones. These epoxyfuranones are obtained along with cyclopropanefuranones by reaction of 4-ethoxy-6-p-tolylsulfinylfuro[3,4-c]pyrazolin-6-ones with MPCBA. In both cases, the formation of the sulfonyl epoxylactones takes place by oxidation of the sulfonylfuran-2(5H)-one resulting from the starting materials. This reaction is completely stereoselective (controlled by the configuration of C-5 of furanone) and results from the nucleophilic attack of the peroxycarboxylate generated by interaction of the reagent with weak basic centres at the substrates. 相似文献
6.
《Tetrahedron: Asymmetry》1999,10(18):3593-3599
Homochiral (5R)-4-bromo-5-(l-menthyloxy)furan-2(5H)-one with stabilized carbanions (from nitroalkanes, malononitrile and ethyl acetoacetate) afforded enantiopure bicyclic compounds in good yield (70–90%). 3-Oxabicyclic[3.1.0]hexan-2-one derivatives were obtained with nitromethane and malonic acid derivatives. However, dihydrofuro[3,4-d]isoxazol-6-one and dihydrofuro[3,4-b]furan-6(4H)-one derivatives were obtained from nitroethane and ethyl acetoacetate, respectively. 相似文献
7.
Tsutomu Kimura Junichiro Nishida Gaku Kashiwamura Gen Kobayashi Tsuyoshi Satoh 《Tetrahedron letters》2014
A novel method for the synthesis of cyclopropane-fused α-chloro-γ-lactones was developed utilizing the nucleophilicity of cyclopropylmagnesium carbenoids. Cyclopropylmagnesium carbenoids were generated from i-PrMgCl and 1-chlorocyclopropyl p-tolyl sulfoxides with a [(phenoxycarbonyl)oxy]methyl group at the 2-position of the cyclopropane ring. The resulting cyclopropylmagnesium carbenoids reacted with an intramolecular carbonate unit to give 1-chloro-3-oxabicyclo[3.1.0]hexan-2-ones in moderate to good yields. The asymmetric synthesis of 1-chloro-3-oxabicyclo[3.1.0]hexan-2-one was achieved using optically active dichloromethyl p-tolyl sulfoxide as a starting material. 相似文献
8.
Michail N. Elinson Sergey K. Feducovich Anatolii N. Vereshchagin Gennady I. Nikishin 《Tetrahedron letters》2005,46(37):6389-6393
Electrolysis of arylidene- or alkylidenemalononitriles and malonate in alcohol in an undivided cell in the presence of sodium halide as mediator results in the stereoselective formation of alkyl (1R,5R,6R)* 6-substituted 5-cyano-4,4-dialkoxy-2-oxo-3-azabicyclo[3.1.0]hexan-1-carboxylates in 50-70% yields. 相似文献
9.
cis-1,5-Dimethyl-2,4-dinitro-2,4-diazabicyclo[3.2.0]heptan-3-one and cis-1,5-dimethyl-2,4-dinitro-2,4-diazabicyclo[3.1.0]hexan-3-one were both synthesized in three steps each from a common precursor, 1,3-diacetyl-4,5-dimelhyl-4-imidazolin-2-one. 相似文献
10.
Alkylation of 7-endo-ethylbicyclo[3.2.0]hept-2-en-6-one (2a) and 7-endo-methylbicyclo[3.2.0]hept-2-en-6-one (2b) with lithium diisopropylamide (LDA) and the appropriate alkyl iodide (methyl and ethyl iodide, respectively) afforded the title compound such that alkylation had occurred exclusively on the exo face of the bicyclo[3.2.0] system. 相似文献
11.
The photochemical reactivity of enantiomerically pure bicyclo[3.1.0]hept-3-en-2-ones has been examined to determine whether a [2+2] cycloaddition with an alkene could be achieved without interference from a photochemically induced skeletal rearrangement. The formation of a tricyclo[5.2.0.02,5]nonan-6-one was indeed the major pathway, exclusively providing the cis-anti-cis isomer. However, the formation of norbornenones was also observed, as was stereochemical scrambling at C6 in the starting material. 相似文献
12.
Jie-You Xue Shi-Xiong Tang Ai-Bin Sun Fan Wu Li-Xin Qiao Yu-Rong Cao Xiao-Lan Wang 《中国化学》1992,10(5):445-450
Cyclopropanedicarboxylic acid anhydride can be converted to 4-substituted 3-oxabicyclo-[3.1.0]hexan-2-one by reaction with Grignard reagents in ether or tetrahydrofuran solution. 相似文献
13.
The solution conformation of bicyclo [3.1.0] hexan-3-one has been obtained by the use of the shifts induced in its 1H and 13C NMR by Yb(fod)3. Refinement of the angle of pucker, ∝, of the 5-membered ring indicates that the molecule adopts a flattened boat conformation with ∝ = 195°. This prediction is supported by ab initio, STO-3G, calculations on the isolated molecule. Use of a two- or four-site model for lanthanide-substrate complexing adequately reproduces the experimental data whereas a one-site binding model is unsatisfactory. The importance of multi-site binding is further emphasised by results for the C2v-symmetric ketone, adamantanone, where only a four-site model gives satisfactory agreement between observed and calculated lanthanide-induced shifts. 相似文献
14.
Syntheses of (±)-2-exo-cyano-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl acetate ( 1 ) and of (±)-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ( 2 ) are reported. The additon of PhSeCl to 1 afforded (±)-5-endo-chloro-2-exo-cyano-1-methyl-6-exo-(phenylselenenyl)-7-oxabicyclo[2.2.1]hept-2-endo-yl acetate ( 6 ), whereas 2 added to PhSeCl with the opposite regioselectivity giving (±)-6-endo-chloro-1-methyl-5-exo-(phenylselenenyl)-7-oxabicyclo[2.2.1]heptan-2-one ( 7 ). These adducts were converted into 5-chloro-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ( 9 ) and 6-chloro-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one ( 10 ), respectively. 相似文献
15.
《Comptes Rendus Chimie》2007,10(9):813-819
The reaction of the isoindole–isoindoline isomers of the thieno[3′,2′:5,6]pyrimido[2,1-a]isoindol-6(10H)-one with aldehydes gives new benzylidene thieno[3′,2′:5,6]pyrimido[2,1-a]isoindol-6(10H)-one derivatives. The structures were assessed with NMR, UV spectroscopy and mass spectra. 相似文献
16.
Pier Giovanni Baraldi Gian Piero Pollini Daniele Simoni Achille Barco Simonetta Benetti 《Tetrahedron》1984,40(4):761-764
A convenient entry to both title compounds 1 and 2, as well as to cis- and trans-4-iodomethyl-bicyclo [3.1.0]-hexan-2-ones 3and 4 and to 4-methyl-bicyclo [3.1.0]-hex-3-en-2-one 5 involving base-promoted reactions of cis- and -trans-3,4-diiodomethylcyclopentanones 6 and 7 is reported, and the behaviour of 6 and 7 towards different bases. bfv40bp4761b 相似文献
17.
A simple synthetic route to 1-p-methoxyphenyl and 1-p-methoxyphenyl-4-methylbicyclo [2.2.1]heptan-7-one 6b,a has been developed through benzilic acid rearrangement of the bicyclo[2.2.1]octandiones 2b,a. The oxidation of 7-hydroxy-1-p-methoxyphenyl-4-methylbicyclo[2.2.1]heptan-7-carboxylic acid 3a with lead tetraacetate gives the carbolactone 7a which is also formed by the reaction of the ketone 6a with m-chloroperbenzoic acid. 相似文献
18.
V. A. Vasin D. Yu. Korovin P. S. Petrov V. V. Razin N. V. Somov 《Russian Journal of Organic Chemistry》2015,51(12):1697-1702
1-Bromotricyclo[4.1.0.02,7]heptane reacted with benzene- and methanesulfonyl thiocyanates in benzene at 20°C via anti addition to the central C1–C7 bicyclobutane bond with formation of 6-endo-bromo-6-exo-thiocyanato-7-syn-(R-sulfonyl)bicyclo[3.1.1]heptanes. Treatment of the benzenesulfonyl thiocyanate adduct with potassium tert-butoxide in THF at 20°C gave 7-endo-(benzenesulfonyl)norpinan-6-one, whereas the reaction with 1,8-diazabicyclo[5.4.0]undec-7-ene in methylene chloride afforded 7-exo-(benzenesulfonyl)-norpinane-6-thione which was converted into 7-exo-(benzenesulfonyl)norpinan-6-one by alkaline hydrolysis. 相似文献
19.
Methyl 1,5-diphenyl- and 5-methyl-1-phenyl-2,3-diazabicyclo[3.1.0]hex-2-ene-6-exo-carboxylates at 138°C undergo decomposition via elimination of nitrogen molecule with formation in each case of five products. Two products are methyl 1,3-diphenyl(or 1-methyl-3-phenyl)bicyclo[1.1.0]butane-2-endo- and -exo-carboxylates, and the three others are derivatives of buta-1,3-diene, methyl (Z)-2-benzylidene-3-phenyl(or 3-methyl)but-3-enoate and methyl (E)- and (Z)-3,4-diphenyl(or 4-methyl-3-phenyl)penta-2,4-dienoates. The formation of these products may be rationalized assuming intermediacy of substituted allylcarbene which undergoes both intramolecular cycloaddition and rearrangements involving 1,2-hydride and 1,2-vinyl shifts. 相似文献
20.
Krishna C. Majumdar Subhojit Ghosh 《Monatshefte für Chemie / Chemical Monthly》2002,133(10):1317-1323
Summary. Regioselective heterocyclization of 3-(cyclohex-2′-enyl)-4-hydroxy-6-methyl pyran-2-one with various reagents afforded different
heterocycles. With N-iodosuccinimide in acetonitrile at 0–5°C it gave 6-methyl-9′-iodo-2′-oxabicyclo[3.3.1]nonano[3,2-c]pyran-2-one, with C5H5NHBr3 or C6H12N4HBr3 in CHCl3 at 0–5°C it furnished 6-methyl-9′-bromo-2′-oxabicyclo[3.3.1]nonano[3,2-c]pyran-2-one. Cold concentrated H2SO4 lead to 6-methyl-2′-oxabicyclo[3.3.1]nonano[3,2-c]pyran-2-one, whereas PdCl2(PhCN)2 in C6H6 at 80°C afforded 9-methyl benzofuro[3,2-c]pyran-2-one.
Corresponding author. E-mail: kcm@klyuniv.ernet.in
Received December 27, 2001. Accepted (revised) March 1, 2002 相似文献