636-82-8Relevant academic research and scientific papers
1-alkenylcalcium iodide: Synthesis and stability
Koehler, Mathias,Goerls, Helmar,Langer, Jens,Westerhausen, Matthias
, p. 5237 - 5239 (2014)
To enhance the scope of heavy calcium-based Grignard reagents, 1,2-dihydro-4-iodonaphthalene (1) was reduced with calcium in THF giving tetrakis(thf) (1,2-dihydronaphth-4-yl)calcium iodide (2). This derivative represents a 1-alkenylcalcium complex based on X-ray structure determination and NMR data. The stability of this compound is significantly reduced compared with the aromatic naphthylcalcium iodide. Complex diversity: The class of heavy Grignard reagents is extended by a 1-alkenylcalcium iodide. This tetrakis(thf) (1,2-dihydronaphth-4-yl)calcium iodide contains a 1-alkenyl moiety based on structural and NMR spectroscopic studies (see figure).
Microenvironment Engineering of Ruthenium Nanoparticles Incorporated into Silica Nanoreactors for Enhanced Hydrogenations
Ren, Xiaomin,Guo, Miao,Li, He,Li, Chengbin,Yu, Liang,Liu, Jian,Yang, Qihua
, p. 14483 - 14488 (2019)
It is a challenging task to promote the activity and selectivity of a catalyst via precisely engineering the microenvironment, an important factor related with the catalytic performance of natural catalysts. Motivated by the water effect in promoting the
Macrolactam Synthesis via Ring-Closing Alkene-Alkene Cross-Coupling Reactions
Goh, Jeffrey,Loh, Teck-Peng,Maraswami, Manikantha
supporting information, p. 9724 - 9728 (2020/12/21)
Reported herein is a practical method for macrolactam synthesis via a Rh(III)-catalyzed ring closing alkene-alkene cross-coupling reaction. The reaction proceeded via a Rh-catalyzed alkenyl sp2 C-H activation process, which allows access to macrocyclic molecules of different ring sizes. Macrolactams containing a conjugated diene framework could be easily prepared in high chemoselectivities and Z,E stereoselectivities.
Preparation method of cyclohexenecarboxylic acid
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Paragraph 0014-0023, (2020/12/08)
The invention discloses a preparation method of cyclohexenecarboxylic acid. The preparation method comprises the following steps of S1, preparing a catalyst: weighing sodium tungstate, performing dissolving with water, slowly dropwise adding hydrochloric
Synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and derivatives thereof
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, (2019/10/01)
The invention discloses a synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and derivatives thereof. The synthetic method comprises the following steps: (1) reacting a substance as described in thespecification with nitromethane at 110 DEG C to obtain a product I as described in the specification, wherein R in the product I is H or CH3; (2) reacting the product I of the step (1) with sodium nitrite and acetic acid at 37 DEG C to obtain a product II as described in the specification; (3) reacting the product II of the step (2) with methanol and concentrated sulfuric acid at 88 DEG C to obtain a product III as described in the specification; and (4) weighing the product III of the step (3), potassium carbonate, palladium on activated carbon and t-butyl hydroperoxide, adding the weighed materials into dichloromethane, carrying out a reaction at 0 DEG C, and allowing temperature to naturally rise to room temperature so as to obtain a product IV, wherein R in the product IV is H or CH3.The synthetic method of the invention is simpler and more efficient, and has high total yield; the toxicity of reagents used in the preparation is smaller than the toxicity of m-methoxybenzoic acid, thionyl chloride and the like used in the prior art; and the method is low in cost, simple and convenient in separation and purification, applicable to large-scale preparation and capable of realizingindustrial mass production. The synthetic method is applicable as a general synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and 4-substituted derivatives thereof.
Iodine-Catalyzed Nazarov Cyclizations
Koenig, Jonas J.,Arndt, Thiemo,Gildemeister, Nora,Neud?rfl, J?rg-M.,Breugst, Martin
, p. 7587 - 7605 (2019/06/27)
The Nazarov cyclization is an important pericyclic reaction that allows the synthesis of substituted cyclopentenones. We now demonstrate that this reaction can be performed under very mild, metal-free reaction conditions using molecular iodine as the catalyst. A variety of different divinyl ketones including aromatic systems undergo the iodine-catalyzed reaction with moderate to very good yields in both polar and apolar solvents. Our mechanistic studies indicate that the Nazarov system is activated through a halogen bond between the carbonyl group and the catalyst, and other modes of action like Br?nsted acid or iodonium ion catalysis are unlikely. Furthermore, addition of iodine to the double bond or a putative iodine-catalyzed cis-trans isomerization of the employed olefins seem not to be an important side reaction here.
Palladium catalyzed carbonylations of alkenyl halides with formic acid to get corresponding Α,Β-unsaturated carboxylic acids and esters
Bartal, Brigitta,Mikle, Gábor,Kollár, László,Pongrácz, Péter
, p. 143 - 149 (2019/02/15)
Palladium-catalysed carbonylation reactions have been developed in the presence of formic acid as carbon monoxide source. α,β-Unsaturated carboxylic acids and esters were synthesized by the transformation of alkenyl halides in moderate to good yields. The selection of the base proved to be crucial regarding the reaction outcome. A set of various substrates were proven under optimised reaction conditions. Compared to aliphatic alcohols, phenols showed excellent reactivity as O-nucleophiles.
Zinc Oxide-Catalyzed Dehydrogenation of Primary Alcohols into Carboxylic Acids
Monda, Fabrizio,Madsen, Robert
supporting information, p. 17832 - 17837 (2018/11/23)
Zinc oxide has been developed as a catalyst for the dehydrogenation of primary alcohols into carboxylic acids and hydrogen gas. The reaction is performed in mesitylene solution in the presence of potassium hydroxide, followed by workup with hydrochloric acid. The transformation can be applied to both benzylic and aliphatic primary alcohols and the catalytically active species was shown to be a homogeneous compound by a hot filtration test. Dialkylzinc and strongly basic zinc salts also catalyze the dehydrogenation with similar results. The mechanism is believed to involve the formation of a zinc alkoxide which degrades into the aldehyde and a zinc hydride. The latter reacts with the alcohol to form hydrogen gas and regenerate the zinc alkoxide. The degradation of a zinc alkoxide into the aldehyde upon heating was confirmed experimentally. The aldehyde can then undergo a Cannizzaro reaction or a Tishchenko reaction, which in the presence of hydroxide leads to the carboxylic acid.
Macrolide Synthesis through Intramolecular Oxidative Cross-Coupling of Alkenes
Jiang, Bing,Zhao, Meng,Li, Shu-Sen,Xu, Yun-He,Loh, Teck-Peng
supporting information, p. 555 - 559 (2018/02/21)
A RhIII-catalyzed intramolecular oxidative cross-coupling between double bonds for the synthesis of macrolides is described. Under the optimized reaction conditions, macrocycles containing a diene moiety can be formed in reasonable yields and with excellent chemo- and stereoselectivity. This method provides an efficient approach to synthesize macrocyclic compounds containing a 1,3-conjugated diene structure.
Preparation of cyclopentyl (f) ene-1-boronic acid frequency that ester method
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Paragraph 0021; 0022, (2016/10/31)
The invention discloses a method of preparing cyclopenten/cyclohexen-1-yl-boronic acid pinacol ester from methyl 1-cyclopentene/cyclohexene-1-carboxylate by three-step continuous operations. The method includes subjecting the raw material to alkaline hydrolysis to form the corresponding 1-alkylene carboxylic acid; performing addition with bromine; performing elimination and decarboxylation at the same time under the existence of DBU or DMAP to produce 1-bromo cyclopentene/cyclohexene; and allowing the 1-bromo cyclopentene/cyclohexene and methoxyboronic acid pinacol ester to form an ester under the existence of magnesium metal by a one-pot process to obtain the cyclopenten/cyclohexen-1-yl-boronic acid pinacol ester. The method is high in continuity, simple and convenient in operations, free of low-temperature reactions, and capable of obtaining the 1-bromo cyclopentene/cyclohexene intermediate with high purity and meeting market demands. The method adopts one-pot-process of Grignard reaction/esterification, so that the method is more convenient in operations and has less by-products, and the product is easier in rectification purification.
