- 4-Phenylspiro[2.2]pentane-1,1-dicarboxylate: synthesis and reactions with EtAlCl2 and 4,5-diazaspiro[2.4]hept-4-ene derivative
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Cyclopropanation of 1-methylidene-2-phenylcyclopropane with dimethyl diazomalonate affords new dimethyl 4-phenyl-spiro[2.2]pentane-1,1-dicarboxylate. On contact with EtAlCl2, this compound undergoes opening of both cyclopropane rings to give dimethyl (2-chloromethyl-3-phenylallyl)malonate. Its EtAlCl2-assisted reaction with methyl 5′-methylspiro[cyclo-propane-1,3′-pyrazoline]-5′-carboxylate proceeds as the 1,3:1′,5′-addition to afford mainly 3-(2-chloroethyl)-1-cyclo-propylmethyl-1H-pyrazoline derivative.
- Denisov, Dmitry A.,Borisov, Denis D.,Potapov, Konstantin V.,Novikov, Roman A.,Tomilov, Yury V.
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p. 417 - 418
(2019/08/20)
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- Bromine radical-mediated sequential radical rearrangement and addition reaction of alkylidenecyclopropanes
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Bromine radical-mediated cyclopropylcarbinyl-homoallyl rearrangement of alkylidenecyclopropanes was effectively accomplished by C-C bond formation with allylic bromides, which led to the syntheses of 2-bromo-1,6-dienes. A three-component coupling reaction
- Kippo, Takashi,Hamaoka, Kanako,Ryu, Ilhyong
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supporting information
p. 632 - 635
(2013/03/14)
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- Bu2SnIH-promoted proximal bond cleavage of methylenecyclopropanes and successive radical cyclization and/or Pd-catalyzed coupling reaction
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The unprecedented regioselective hydrostannation of methylenecyclopropanes to give vinyltins was achieved using dibutyliodotin hydride (Bu2SnIH), which could be applied to intramolecular radical cyclization. Copyright
- Hayashi, Naoki,Hirokawa, Yusuke,Shibata, Ikuya,Yasuda, Makoto,Baba, Akio
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p. 2912 - 2913
(2008/09/20)
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- Luminescence system, method of luminescence, and chemical substance for luminescence
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An object of the present invention is to provide, inexpensively and safely, a luminescence system, a method of luminescence, and a luminescent substance based on a novel luminescence mechanism that luminesces at high efficiency. The present invention rela
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Page/Page column 11
(2008/06/13)
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- Ni-complex-catalysed addition polymerisation of 2-phenyl-1-methylenecylopropane to afford a polymer with cyclopropylidene groups
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π-Allyl-nickel complexes initiated addition polymerisation of 2-phenyl-1-methylenecyclopropane to give a polymer with three-membered rings; the formed polymer showed a high Tg and negligible thermal decomposition up to 300°C.
- Takeuchi, Daisuke,Osakada, Kohtaro
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p. 646 - 647
(2007/10/03)
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- Pd-catalyzed ring-opening copolymerization of 2-aryl-1-methylenecyclopropanes with CO to afford polyketones via alternating insertion of the two monomers and C - C bond activation of the three-membered ring
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Pd-bpy complexes catalyze the ring-opening copolymerization of 2-aryl-1-methylenecyclopropanes with CO, affording the new polyketones composed of ring-opened structural units only. Kinetic and isotope-labeling studies revealed the mechanism of the reactio
- Kim, Sunwook,Takeuchi, Daisuke,Osakada, Kohtaro
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p. 762 - 763
(2007/10/03)
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- Reaction of 1-aryl-2-methylenecyclopropanes with rhodium(I) complexes leading to ring opening isomerization and π co-ordination of the C=C double bond
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1-Aryl-2-methylenecyclopropanes reacted with [RhCl(PPh3)3] at 50°C to give [RhCl(η4-CH2=CArCH=CH2)(PPh 3)2] (Ar = C6H5 1a, C6H4F-p 1b, C6H4Me-p 1c or C6H4OMe-p? 1d) via ring opening isomerization of the substrate and its subsequent co-ordination to Rh. The diene-co-ordinated rhodium complexes have been characterized by X-ray crystallography and NMR spectroscopy. Similar reaction at 0°C afforded the rhodium(I) complexes with πco-ordinated 1-aryl-2-methylenecyclopropane, [RhCl(η2-CH2=CCH2CHAr)(PPh 3)2] (Ar = C6H5 2a, C6H4F-p 2b, C6H4Me-p 2c or C6H4OMe-p 2d). Exchange of the ligand of 2a with added 1-aryl-2-methylenecyclopropanes occurs reversibly at 30-45°C with the thermodynamic parameters of the reactions 2a + CH2=CCH2CHC6H4X-p ? 2b (or 2c) + CH2=CCH2CHC6H5 being ΔH° = -10.3 kJ mol-1 and ΔS° = -32 J K-1 mol-1 for X = F and ΔH° = 2.2 kJ mol-1 and ΔS° = -2.6 J K-1 mol-1 for X = Me, respectively, at 298 K. The structure of a PEt3 co-ordinated analog, [RhCl(η2-CH2=CCH2CHC6H 4Me-p)(PEt3)2] 3c, has been determined by X-ray crystallography. The reaction of 1-methylene-2-phenylcyclopropane with [RhCl(PPh3)3] at 25°C gave a mixture of 1a and 2a. Heating of a benzene solution of 2a at 50°C turned it into 1a in low yield (3)3] at 50°C.
- Osakada, Kohtaro,Takimoto, Hisami,Yamamoto, Takakazu
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p. 853 - 859
(2007/10/03)
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- Reactions of the Lithium Salts of the Tribenzylidenemethane Dianion, Diphenylacetone Dianion, and Related Compounds
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Potentially synthetically useful reactions of the dilithium salts of the title dianions have been investigated. Electrophilic quenching with a variety of reagents usually leads to the expected products in good yield. Quenching the diphenylacetone dianion with 1 equiv of trimethylchlorosilane, however, gives a good yield of 1,3-diphenylallene obtained by formal elimination of a trimethylsiloxy anion from an intermediate monoquenched monoanion salt. NMR studies, however, do not reveal the intermediacy of the 1,3-diphenyl-2-(trimethylsiloxy)allyl anion but rather suggest that the initial reaction site is at carbon, rather than oxygen. Oxidation of the dianions leads either to ring closure or dimerization for the tribenzylidenemethane dianion and to dimerization for the diphenylacetone dianion. The dimerization reactions are stereospecific, both with respect to the two new stereocenters produced and for the double bonds of the bis-silyl enol ether products if the dimeric bis-enolate dianion products are quenched with trimethylchlorosilane.
- Witt, Ortrun,Mauser, Harald,Friedl, Thomas,Wilhelm, Dieter,Clark, Timothy
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p. 959 - 967
(2007/10/03)
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- Mechanistic study of the reaction of 1,1-dihalo-2-methyl-2-phenylpropanes with LDA. Evidence for radical and carbene pathways
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An attempt was made to determine the mechanisms involved in the reactions of the model systems 1,1-dichloro-2-methyl-2-phenylpropane (1) and 1,1-diiodo-2-methyl-2-phenylpropane (2) with LDA.These systems were chosen as ones capable of providing evidence for the formation of radical as well as carbene products.The techniques employed in investigating the mechanistic features of these reactions involved studying the effect of the leaving group, the effect of radical and carbene trapping agents on the product distribution, and isotopic tracer experiments using labeled solvent (THF-d8) and nucleophile (LDA-d2).The major product of the reaction of the geminal dichloride (1) is thought to be derived from a chlorocarbene, whereas the geminal diiodide (2) appears to form products derived from both carbene and radical intermediates.On the basis of the results of radical trapping experiments and those of deuterium-labeling experiments, evidence is presented to support the notion that products A, E, and H are derived from a radical precursor.In addition, products A and H are also believed to be formed from the vinilyc halide D (or B) and the monoiodide E, respectively.Reasonable mechanisms for the formation of the other products formed in these reactions have been proposed on the basis of the available data.
- Ashby, E. C.,Mehdizadeh, Ali,Deshpande, Abhay K.
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p. 1322 - 1330
(2007/10/03)
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- Energy Well of the Orthogonal Trimethylenemethane. - 1-Methylene-2-phenylcyclopropane Thermolysis
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From the heat of hydrogenation of 5, the activation enthalpy for the racemization of the title compound, and the oxygen dependance of the trapping rate of the intermediate diradical 8 the energy profile for the degenerate methylene-cyclopropane rearrangement can be constructed, which leads to heats of formation for the triplet and singlet state of the diradical 8 of ΔHf0 93.9 and 95.6 kcal mol-1, respectively. - Key Words: Diradicals / Oxygen trapping / Energy well / Heat of formation / Heat of hydrogenation
- Roth, Wolfgang R.,Winzer, Markus,Lennartz, Hans-Werner,Boese, Roland
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p. 2717 - 2726
(2007/10/02)
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- 1-(Phenylsulfonyl)-2-(trimethylsilyl)ethane: A Valuable Intermediate for Synthesis of Olefins, Allyltrimethylsilanes, β-Trimethylsilyl Ketones, Vinyl Sulfones, 2-(Phenylsulfonyl)allyl Alcohols, and Varied Trimethylsilyl Derivatives
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1-(Phenylsulfonyl)-2-(trimethylsilyl)ethane (1), prepared from 1-(trimethylsilyl)-2-(thiophenoxy)ethane and hydrogen peroxide, is converted by n-butyllithium to 1-(phenylsulfonyl)-1-lithio-2-(trimethylsilyl)ethane (2).Primary halides effect alkylation of 2 to 2-(phenylsulfonyl)-1-(trimethylsilyl)alkanes (3), reactions of which with n-butyllithium and then primary halides give higher 2-(phenylsulfonyl)-1-(trimethylsilyl)alkanes (5).Debenzenesulfonyltrimethylsilylation of 3 and 5 occurs efficiently with tetra-n-butylammonium fluoride (6) to yield mono- and disubstituted terminal olefins (7 and 8, respectively). 2-(Phenylsulfonyl)-3-(trimethylsilyl)-1-alkanols (14) result from reactions of 2 with aldehydes and ketones and then acidification.Allyltrimethylsilanes (18) are obtained by reductive elimination of mesylates (17) of 14 with sodium amalgam in methanolic disodium hydrogen phosphate. 2-(Phenylsulfonyl)-3-(trimethylsilyl)-1-propene (23), a 1-cationic-2-anionic equivalent (33), is preparable by (1) condensation of 1 and formaldehyde to 2-(phenylsulfonyl)-3-(trimethylsilyl)-1-propanol (24), (2) conversion of 24 by triphenylphosphine/carbon tetrachloride to 1-chloro-2-(phenylsulfonyl)-3-(trimethylsilyl)propane (25), and (3) elimination of 25 with triethylamine. β-Trimethylsilyl ketones (35) are produced by sodium amalgam reduction of α-phenylsulfonyl β-trimethylsilyl ketones (34) obtained by oxidation of 2-(phenylsulfonyl)-3-(trimethylsilyl)-1-propanols (14, R2 = H) with chromic acid sulfonic acid in acetone.Acidification of the adducts from 2 and epoxides yields 3-(phenylsulfonyl)-4-(trimethylsilyl)-1-butanols (38).Primary and secondary alcohols 38 are converted by chromic acid/sulfuric acid to 3-phenyl sulfonyl 4-trimethylsilyl aldehydes and ketones (39). n-Butyllithium effects cyclization of methanesulfonates (40) of 37 to 1-(phenylsulfonyl)-1-cyclopropanes (42) with displacement of lithium methanesulfonate. 1-(Phenylsulfonyl)-2-n-hexyl-1-cyclopropane (46a) and 1-(phenylsulfonyl)-2-phenyl-1-cyclopropane (46b) are eliminated by 6 to 1-n-hexyl-2-methylenecyclopropane (47a) and 1-methylene-2-phenylcyclopropane (47b), respectively. 2-(Phenylsulfonyl)-1-alkenes (49) are prepared by reactions of 6 with 2-(phenylsulfonyl)-2-chloro-1-(trimethylsilyl)alkanes (48) obtained (1) from tert-butyl hypochlorite and 2-(phenylsulfonyl)-2-lithio-1-(trimethylsilyl)alkanes(4) and/or (2) by reaction of 1-(phenylsulfonyl)-1-chloro-2-(trimethylsilyl)ethane (50) with n-butyllithium and alkylations of the resulting 1-(phenylsulfonyl)-1-chloro-1-lithio-2-(trimethylsilyl)ethane (51).Synthesis of 50 is best effected by base-catalyzed cleavage of 3-(phenylsulfonyl)-3-chloro-4-(trimethylsilyl)-2-butanone (54) prepared from 1-acetyl-1-phenylsulfonyl)-2-(trimethylsilyl)ethane (53) and ...
- Hsiao, C.-N.,Shechter, H.
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p. 2688 - 2699
(2007/10/02)
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