- An efficient method for the synthesis of 2′,3′-nonsubstituted cycloalkane-1,3-dione-2-spirocyclopropanes using (2-bromoethyl)-diphenylsulfonium trifluoromethanesulfonate
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An efficient and practical synthesis of 2′,3′-nonsubstituted cyclohexane-1,3-dione-2-spirocyclopropanes using a sulfonium salt was achieved. The reaction of 1,3-cyclohexanediones and (2-bromoethyl)diphenylsulfonium trifluoromethanesulfonate with powdered K2CO3 in EtOAc at room temperature (r.t.) provided the corresponding spirocyclopropanes in high yields. The synthetic method was also applied to 1,3-cyclopentanedione, 1,3-cycloheptanedione, 1,3-indanedione, acyclic 1,3-diones, ethyl acetoacetate, and Meldrum's acid.
- Nambu, Hisanori,Ono, Naoki,Hirota, Wataru,Fukumoto, Masahiro,Yakura, Takayuki
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p. 1763 - 1768
(2016/12/09)
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- Synthesis and structural characterization of (CH2)n-bridged indenyl-pyrazoles and their cyclopentadienyl nickel(II) complexes
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A new class of (CH2)n-bridged indenyl-pyrazoles [4-{Ind-(CH2)n}-RR′PzH] (Ind = 1H-inden-3-yl, n = 1-3, RR′Pz = 3,5-disubstituted pyrazolato) were synthesized. Reactions of the indenyl-functionalized pyrazoles wi
- Tan, Weiqiang,Yu, Zhengkun,Liu, Bing,Wu, Kaikai,Liu, Zishuang,Chen, Jinzhu
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scheme or table
p. 199 - 206
(2009/04/13)
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- Observations in the synthesis of the core of the antitumor illudins via an enyne ring closing metathesis cascade
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Observations concerning the synthesis of the core spirocyclic AB-ring system of illudins using an enyne ring closing metathesis (EYRCM) cascade are discussed. Substituent effects, in addition to optimization of the reaction conditions and the olefin tethe
- Movassaghi, Mohammad,Piizzi, Grazia,Siegel, Dustin S.,Piersanti, Giovanni
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scheme or table
p. 5489 - 5492
(2010/01/11)
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- Enantioselective total synthesis of (-)-acylfulvene and (-)-irofulven
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(Chemical Equation Presented) We report our full account of the enantioselective total synthesis of (-)-acylfulvene (1) and (-)-irofulven (2), which features metathesis reactions for the rapid assembly of the molecular framework of these antitumor agents. We discuss (1) the application of an Evans Cu-catalyzed aldol addition reaction using a strained cyclopropyl ketenethioacetal, (2) an efficient enyne ring-closing metathesis cascade reaction in a challenging setting, (3) the reagent IPNBSH for a late-stage reductive allylic transposition reaction, and (4) the final RCM/dehydrogenation sequence for the formation of (-)-acylfulvene (1) and (-)-irofulven (2).
- Siegel, Dustin S.,Piizzi, Grazia,Piersanti, Giovanni,Movassaghi, Mohammad
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scheme or table
p. 9292 - 9304
(2010/03/04)
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- Imidazolium salts as phase transfer catalysts for the dialkylation and cycloalkylation of active methylene compounds
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The efficient synthesis of 1,1-disubstituted derivatives and the construction of cyclopropane and cyclopentane ring systems via dialkylation and cycloalkylation reactions of active methylene compounds using imidazolium salts as phase transfer catalyst is described. The dialkylation and cycloalkylation reactions of active methylene compounds in the presence of readily available imidazolium salts (ionic liquids) as phase transfer catalysts were performed to afford the respective dialkylated or cycloalkylated products. This method is very efficient for the synthesis of 1,1-disubstituted derivatives and cyclopropane and cyclopentane ring systems in a facile manner.
- Muthusamy, Sengodagounder,Gnanaprakasam, Boopathy
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p. 635 - 638
(2007/10/03)
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- Microwave assisted phase transfer catalysis: An efficient solvent free method for the synthesis of cyclopropane derivatives
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Microwave assisted solvent free synthesis of cyclopropane derivatives 2a-e starting from active methylene compounds 1a-e and 1,2-dibromoethane under phase transfer conditions is described.
- Gumaste,Khan, Asgar J.,Bhawal,Deshmukh
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p. 420 - 422
(2007/10/03)
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- Electrosynthesis of cyclopropane derivatives by a Perkin-type reaction
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Electrolysis of active methylene compounds at a Pt cathode in MeCN in the presence of vicinal dihaloalkanes leads to cyclopropane derivatives in yields up to 90percent.In the cases of CH-acids with low pKa it is expedient to apply more active dihaloalkanes, while for CH-acids with higher pKa the desired product yields may be raised using electrogenerated bases. - Key words: CH-acids; 1,2-dihaloalkanes; cyclopropanes; electrosynthesis; electroreduction; electronegative bases; azobenzene.
- Petrosyan, V. A.,Vasil'ev, A. A.,Tatarinova, V. I.
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- THE REACTION OF DIPHENYL DISULFIDE WITH 3,3-DIACETYLPROPYL MERCURY CHLORIDE
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The enolate anion derived from (CH3CO)2CHCH2CH2HgCl undergoes cyclization with demercuration to form 1,1-diacetylcyclopropane.The presence of Ph2S2 prevents cyclization and leads to phenylthylation at carbon and at mercury.In the absence of base Ph2S2 reacts with (CH3CO)2CHCH2CH2HgCl in a photostimulated chain reaction to form (CH3CO)2CHCH2CH2SPh. Key words: Diphenyl disulfide; mercury chloride; photostimulated reaction
- Russell, Glen A.,Shi, Bing Zhi
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- CATHODIC SYNTHESIS OF CYCLOPROPANE DERIVATIVES BY THE ELECTROLYSIS OF COMPOUNDS WITH AN ACTIVATED METHYLENE GROUP IN 1,2-DICHLOROETHANE
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The cathodic electrolysis of compounds with an activated methylene group in 1,2-dichloroethane leads to 1,1-disubstituted cyclopropanes.The current yield of these cyclopropane derivatives depends on the CH-acidity of the starting compounds and has a maximum at pKa ca.13.
- Vasil'ev, A. A.,Tatarinova, V. I.,Petrosyan, V. A.
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p. 631 - 633
(2007/10/02)
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- Preparation and Cleavage of Some Cyclopropane Derivatives
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Alkylation of active methylene compounds with 1,2-dibromoethane using anhyd.K2CO3/DMF at room temperature gives cyclopropane derivatives which undergo selective transformation by simple methods.Cyclopropanes, obtained by the condensation of α-diazoacetophenones with olefins, are cleaved to trisubstituted olefins with Grignard reagent.Hydration of the products has also been studied.
- Podder, Ranjan Kumar,Sarkar, Ranjit Kumar,Ray, Suvas C.
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p. 530 - 536
(2007/10/02)
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- SYNTHESIS OF GEM-DISUBSTITUTED ETHYLENE AND ACETYLENE DERIVATIVES OF THE CYCLOPROPANE SERIES BASED ON 1,1-DIACYLCYCLOPROPANES
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Methods for the conversion of 1,1-diacylcyclopropanes into gem-disubstituted dienes and acetylenes of the cyclopropene series were investigated: a) Reduction followed by dehydration of the diols; b) conversion of the diketones into bistosylhydrazones and treatment of the latter with methyllithium; c) dehydrohalogenation of gem-di(1-halogenoalkyl)cyclopropanes by the action of bases.Dehydration leads to intramolecular nucleophilic opening of the three-membered ring. 1,1-Divinylcyclopropanes and stereoisomeric 1,1-di(1-propenyl)cyclopropanes were obtained by two different methods, and the corresponding diynes and enynes were synthesized from them by bromination followed by dehydrobromination. 1,1-Di(1-propynyl)cyclopropane can be obtained by alkylation of 1,1-diethynylcyclopropane and also directly from 1,1-divinylcyclopropane without isolation of the intermediate 1,1-diethynylcyclopropane.
- Zefirov, N. S.,Kozhushkov, S. I.,Kuznetsova, T. S.,Gleiter, R.,Eckert-Maksic, M.
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- CYCLOALKYLATION BY THE α,ω-DIBROMIDES OF COMPOUNDS CONTAINING AN ACTIVATED METHYLENE GROUP AS A METHOD FOR THE SYNTHESIS OF 1,1-DISUBSTITUTED CYCLOALKENES
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A convenient preparative method was developed for the cycloalkylation of active methylene compounds, including β-diketones, by the dibromides BrCH2(CH2)nCH2Br (n = 0,1,2) in the presence of an excess of potassium carbonate in DMSO.The reaction gives high yields for the dibromides with n = 0 and 2, whereas the formation of cyclobutanes (n=1) is complicated by O,C-alkylation.The 1-substituted 1-acylcyclopropanes undergo thermal isomerization to the corresponding dihydrofuranes.
- Zefirov, N. S.,Kuznetsova, T. S.,Kozhushkov, S. I.,Surmina, L. S.,Rashchupkina, Z. A.
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p. 474 - 480
(2007/10/02)
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- FACILE SYNTHESIS OF 1,3-DIACETYL-2-METHYLCYCLOPENTENE A VERSATILE SYNTHETIC INTERMEDIATE
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Convenient access to 1,3-diacetyl-2-methylcyclopentene 2 is reported by three routes : acetylation of methylcyclopentene ( or cyclo-hexane ), condensation of acetylacetone with 1,2-dibromoethane, and the isomerisation of O-acetylated dienolate of 1-acetyl-2-methylcyclopentene.The process of isomerisation provides best results and its mechanism is discussed.
- Pardo, Roselyne,Santelli, Maurice
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p. 3843 - 3846
(2007/10/02)
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