- Ni-catalyzed reductive antiarylative cyclization of alkynones
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A new catalyst system for the antiarylative cyclization of alkynones and aryl halides through a reductive cross-coupling strategy is developed. The transformation proceeds smoothly in the absence of organometallic reagents and features high functional group tolerance. This method provides an effective platform to access a wide variety of synthetically useful endocyclic tetrasubstituted allylic alcohols in a stereoselective manner.
- Zhou, Zhijun,Liu, Wenfeng,Kong, Wangqing
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supporting information
p. 6982 - 6987
(2020/09/15)
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- Aluminum Chloride-Mediated Dieckmann Cyclization for the Synthesis of Cyclic 2-Alkyl-1,3-alkanediones: One-Step Synthesis of the Chiloglottones
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Cyclic 2-alkyl-1,3-alkanediones are ubiquitous structural motifs in many natural products of biological importance. Reported herein is an AlCl3·MeNO2-mediated Dieckmann cyclization reaction of general synthetic utility that enables direct access to complex 2-alkyl-1,3-dione building blocks from readily available dicarboxylic acid and acid chloride substrates. This new strategy enables direct synthetic access to the chiloglottone plant pheromones from commercial material in a single synthetic transformation.
- Armaly, Ahlam M.,Bar, Sukanta,Schindler, Corinna S.
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supporting information
p. 3958 - 3961
(2017/08/15)
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- Method for preparing 2-methyl-1,3-dicarbonyl derivative
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The invention discloses a method for preparing a 2-methyl-1,3-dicarbonyl derivative. A 1,3-dicarbonyl derivative serves as an initiator, raw materials are easy to obtain, and a great variety of raw materials are available. The product obtained through the method has high type diversity and can be used directly or used for other further reactions. Besides, only organic peroxides and a catalytic amount of inorganic copper salt are used, so that cost is low. According to the method, a reaction is conducted in air, reaction conditions are mild, pollution is small, reaction time is short, the yield of the target product is high, reaction operation and aftertreatment are easy, and the method is suitable for industrial production.
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Paragraph 0044
(2016/10/08)
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- Gold(III) complexes catalyze deoximations/transoximations at neutral pH
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Golden solution: A neutral solution of AuBr3, containing [AuBr2(OH)2]- in equilibrium with [AuBr 3(OH)]- and [AuBr4]-, promotes the chemoselective hydrolysis of robust oximes into carbonyl compounds without racemization (see scheme). The food additive diacetyl acts as a NH 2OH-trapping agent, thus avoiding the formation of gold nanoparticles and allows the reaction to run catalytically. Copyright
- Isart, Carles,Bastida, David,Bures, Jordi,Vilarrasa, Jaume
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experimental part
p. 3275 - 3279
(2011/05/12)
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- Palladium-catalyzed synthesis of substituted cycloheptane-1,4-diones by an asymmetric ring-expanding allylation (AREA)
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(Chemical Equation Presented) The right AREA: Functionalized, seven-and eight-membered carbocycles are available from an asymmetric Pd-catalyzed decarboxylative fragmentation of strained bicyclo[3.2.0]heptane-2-ones (see scheme, dba = trans,trans-dibenzylidene-acetone). The products were formed in a sequence of [2+2] cycloaddition, retro-aldol reaction, and asymmetric allylation of ketone enolates.
- Schulz, Sabrina R.,Blechert, Siegfried
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p. 3966 - 3970
(2008/03/12)
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- Substituent Effects on the CC Bond Strength, 16. - Thermal Stability and Enthalpies of Formation of β-Dicarbonyl Compounds. - Stabilisation Enthalpies of α,α'-Diketoalkyl Radicals
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The geminal interactions of the two carbonyl groups in seven β-diketones of the type 8-9 and 11-13 were estimated from their enthalpies of formation, which were deduced from their heats of combustion and enthalpies of vaporization.The radical stabilisation enthalpies RSE of the α,α'-diketoalkyl radicals 9-13 were obtained from the enthalpies of activation ΔH(excit.) of thermal CC bond cleavage of eight model compounds of the type 9-13 by their comparison with ΔH(excit.) of comparable hydrocarbons of similar strain.For non-cyclic α,α'-diacylalkyl radicals and six-membered cyclic ones RSE = 54.8 +/- 1.3 kJ mol-1 was determined, which indicates an additive stabilisation by two carbonyl groups. - Key Words: Enthalpies of formation/ Geminal substituents, energetic interaction of/ Bond cleavage, C-C, kinetics of/ Radicals, stability of/ Increments, thermochemical/ Bond strength, substituent effects on
- Noelke, Margot,Verevkin, Sergej P.,Beckhaus, Hans-Dieter,Ruechardt, Christoph
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- AN IMPROVED PINACOL REARRANGEMENT FOR THE SYNTHESIS OF 2-ALKYL-1,3-CYCLOPENTADIONES
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2-Methyl, 2-ethyl and 2-isopropyl-1,3-cyclopentadiones are prepared by a modification of the method described by Nakamura, et al.
- Martinez, Rodolfo A.,Rao, Pemmaraju N.,Kim, Hyun K.
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p. 373 - 378
(2007/10/02)
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- Ring-Expansion Reactions Catalyzed by Hydrophobic Vitamin B12 in Synthetic Bilayer Membrane
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Heptapropyl cobyrinate perchlorate catalyzed the ring-expansion reactions, which convert 2-methyl-1,3-cyclopentanedion and 3-methyl-2-pyrrolidinone into 1,4-cyclohexanedione and 2-piperidinone, respectively, in single-compartment bilayer vesicles.
- Murakami, Yukito,Hisaeda, Yoshio,Ohno, Teruhisa,Matsuda, Yoshihisa
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p. 621 - 624
(2007/10/02)
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- Thermal Isomerization of Isodicyclopentadiene and Its Cycloaddition Reactions
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Isodicyclopentadiene (4) undergoes a sigmatropic hydrogen shift at elevated temperatures (170-180 deg C) to form an isomeric, higly reactive diene intermediate 5 which readily undergoes cycloaddition reactions with dienophiles like dichlorovinylene carbonate (DCVC, 8), vinylene carbonate (VC, 7), and maleic anhydride (9).In all cases addition to 5 occurs exclusively from the exo face.While 7 and 8 under these high-temperature conditions give one major addition product each (12 and 13, respectively), in accord with Alder's rule, 9 at high temperature yields the two isomeric product 15 and 16 initially in the ratio 1:3 of which the isomer 16 (Alder's rule product) on prolonged heating is converted into the stable isomer 15 (anti Alder's rule product).The cycloaddition reactions of 4-cyclopentene-1,3-dione (10), 2,2-dimethyl-4-cyclopentene-1,3-dione (11), and dimethyl acetylenedicarboxylate (28) with 4 and 5 are also discussed.In situ formation of 5 at 0 deg C by photolytic cleavage of diketone 14 is proved by trapping 5 with maleic anhydride.X-ray crystallographic data are provided for the adducts 12, 13, 15, 16, and 21.
- Subramanyam, Ravi,Batlett, Paul D.,Iglesias, Graciela Y. Moltrasio,Watson, William H.,Galloy, Jean
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p. 4491 - 4498
(2007/10/02)
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- Synthesis of 2-alkyl-cyclopentan-1,3-diones
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2-Lower alkyl-cyclopentan-1,3-diones are prepared in high yield by cyclization of gamma-ketoesters in the presence of a colloidal suspension of an alkali metal primary lower alcoholate.
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