13979-22-1Relevant academic research and scientific papers
New One-Pot Preparation of α,β-Unsaturated Carboxylic Acid Esters from Carbonyl Compounds
Olah, George A.,Wu, An-hsiang,Farooq, Omar,Prakash, G. K. Surya
, p. 537 - 538 (1988)
A series of α,β-unsaturated carboxylic acid esters have been prepared by the reaction of carbonyl compounds with alkoxy acetylide anions generated in situ from the readily available α-chloroacetaldehyde dialkyl acetals in the presence of lithium diisopropylamide, followed by aqueous acidic work-up.
Direct bromocarboxylation of arynes using allyl bromides and carbon dioxide
Zhang, Yu,Xiong, Wenfang,Cen, Jinghe,Yan, Wuxin,Wu, Yaodan,Qi, Chaorong,Wu, Wanqing,Jiang, Huanfeng
, p. 12304 - 12307 (2019)
An unprecedented three-component coupling involving arynes, allyl bromides, and CO2 is described, providing efficient and facile access to structurally diverse ortho-brominated aryl esters. Unlike the conventional role played in organic synthesis as electrophiles, organic bromides served as nucleophiles in this reaction, affording a new approach to multicomponent reactions (MCRs) involving aryne intermediates. Additionally, Hammett analysis suggests that two reaction mechanisms exist, depending on the electronic nature of the cinnamyl bromides used.
Iron-Catalyzed Stereoselective Cross-Coupling Reactions of Stereodefined Enol Carbamates with Grignard Reagents
Rivera, Ana Cristina Parra,Still, Raymond,Frantz, Doug E.
, p. 6689 - 6693 (2016)
A practical and highly stereoselective iron-catalyzed cross-coupling reaction of stereodefined enol carbamates and Grignard reagents to yield tri- and tetrasubstituted acrylates is reported. A facile method for the stereoselective generation of these enol carbamates has also been developed. Ironing out olefin synthesis: A practical and highly stereoselective iron-catalyzed cross-coupling reaction between stereodefined enol carbamates and alkyl Grignard reagents yields tri- and tetrasubstituted acrylates. A facile method for the stereoselective generation of these enol carbamates is also reported.
An efficient procedure for the diastereoselective dehydration of β-hydroxy carbonyl compounds by CeCl3·7H2O/Nal system
Bartoli, Giuseppe,Bellucci, Maria C.,Petrini, Marino,Marcantoni, Enrico,Sambri, Letizia,Torregiani, Elisabetta
, p. 1791 - 1793 (2000)
(Formula presented) The dehydration of β-hydroxy ketones and β-hydroxy esters is a synthetically useful method for the conversion of these compounds to the corresponding α,β-unsaturated derivatives. Cerium(III) chloride heptahydrate in combination with sodium iodide in refluxing acetonitrile acts as an efficient reagent for this conversion. The present procedure, which utilizes cheap and "friendly" reagents, offers the corresponding (E)-enones in good yields as the only isolable products.
Imidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium-arene catalysts for olefin metathesis and cyclopropanation
Tudose, Adriana,Demonceau, Albert,Delaude, Lionel
, p. 5356 - 5365 (2006)
Five imidazol(in)ium-2-carboxylates bearing cyclohexyl, mesityl, or 2,6-diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding N-heterocyclic carbenes (NHCs) by reaction with carbon dioxide. They were characterized by IR and NMR spectroscopies, and by TGA. Their ability to act as NHC precursors for in situ catalytic applications was probed in ruthenium-promoted olefin metathesis and cyclopropanation reactions. When visible light induced ring-opening metathesis polymerization of cyclooctene or cyclopropanation of styrene with ethyl diazoacetate were carried out at 60 °C in the presence of [RuCl2(p-cymene)]2, the NHC · CO2 adducts and their NHC · HX counterparts (X = Cl, BF4) displayed similar activities. When metathesis polymerizations were performed at room temperature, the carboxylates proved far superior to the corresponding imidazol(in)ium acid salts. They displayed the same level of activity as the preformed RuCl2(p-cymene)(IMes) complex, whereas the combination of NHC · HX and KO-t-Bu were almost totally inactive. Results obtained for cyclopropanation reactions at room temperature did not show such a large discrepancy of behavior between the two types of adducts.
THE APPLICATION OF HIGH PRESSURE TO SOME DIFFICULT WITTIG REACTIONS
Isaacs, Neil S.,El-Din, Ghazi Najim
, p. 2191 - 2192 (1987)
Wittig reactions, previously shown to be favourably accelerated under pressure have been carried out between the stabilized ylides carboethoxymethylenetriphenylphosphorane and carboethoxyethylidinetriphenylphosphorane with a variety of ketones at 9-10 kbar pressure.Succesful formation of tri- and tetra-substituted ethylenes are reported.
Experimental and theoretical studies of the [3,3]-sigmatropic rearrangement of prenyl azides
Porta, Exequiel O.J.,Vallejos, Margarita M.,Bracca, Andrea B.J.,Labadie, Guillermo R.
, p. 47527 - 47538 (2017)
[3,3]-Sigmatropic rearrangement of isoprenyl azides has been extensively investigated in an experimental and theoretical level. Prenylazides with different chain lengths and phenyl prenylazide have been synthesized. NMR analysis of each azide has been made to determine the equilibrium composition, showing the predominance of primary allyl azides over the tertiary ones and E over Z isomer, regardless of the chain length, temperature, solvent or the regiochemistry of the precursor isoprenyl alcohol. It was determined that phenyl prenylazides do not experience [3,3]-sigmatropic rearrangement. In order to rationalize the experimental results and to gain insight in the mechanism of the [3,3]-sigmatropic rearrangement of prenylazides a theoretical study was performed using density functional theory and the QTAIM approach.
Stereoselective synthesis of 3-alkylcinnamic esters via coupling reaction of (2Z)-3-(aryltelluro) cinnamic esters in presence of CuI
Huang, Xian,Zhao, Chang-Qiu
, p. 237 - 241 (1997)
Coupling reaction of (2Z)-3-(aryltelluro) cinnamic esters with Grignard reagents in presence of CuI produced trisubstituted alkenes containing ester groups with retention of configuration.
Microwave Accelerated Wittig Reactions of Stabilized Phosphorus Ylides with Ketones under Solvent-Free Conditions
Spinella, Aldo,Fortunati, Tancredi,Soriente, Annunziata
, p. 93 - 94 (1997)
Microwave irradiation accelerates some difficult Wittig reactions of stable phosphorus ylides (e.g. 1) with ketones. Irradiation in a domestic microwave oven of the mixture of reactants, in absence of solvents, allowed to obtain, in shorter times, an impr
Visible-Light-Induced Meerwein Fluoroarylation of Styrenes
Tang, Hai-Jun,Zhang, Bin,Xue, Fei,Feng, Chao
supporting information, p. 4040 - 4044 (2021/05/26)
An unprecedented approach for assembling a broad range of 1,2-diarylethane derivatives with fluorine-containing fully substituted carbon centers was developed. The protocol features straightforward operation, proceeds under metal-free condition, and accommodates a large variety of synthetically useful functionalities. The critical aspect to the success of this novel transformation lies in using aryldiazonium salts as both aryl radical progenitor and also as single electron acceptor which elegantly enables a radical-polar crossover manifold.
