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Substitution Reaction (substitution + reaction)
Kinds of Substitution Reaction Selected AbstractsEnantioselective Copper-Catalyzed Allylic Substitution Reaction with Aminohydroxyphosphine LigandADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009Naohiko Yoshikai Abstract A proline-derived aminohydroxyphosphine ligand induced excellent regio- and enantioselectivities (SN2,:SN2>94:6, 94,97% ee) in the copper-catalyzed substitution reaction of cinnamyl phosphates with Et2Zn. A computational modelling study of the reaction pathway suggests that the displacement of the leaving group takes place in an ordered, anti -fashion through simultaneous copper,olefin and zinc,oxygen interactions, which is critical for the enantioselection. [source] ChemInform Abstract: Remarkable Effect of Phosphine on the Reactivity of O,P-Acetal,Efficient Substitution Reaction of O,P-Acetal.CHEMINFORM, Issue 42 2010Hiromichi Fujioka Abstract Tri(o-tolyl)phosphine is identified as a good nucleophile for the formation of intermediate O,P-acetals from O,O-acetals (I) and a good leaving group for the successive nucleophilic substitution. [source] ChemInform Abstract: Tandem Ir-Catalyzed Allylic Substitution Reaction of Allyl Sulfinates and Isomerization.CHEMINFORM, Issue 25 2010Qing-Long Xu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Nucleophilic Substitution Reaction at an sp2 Carbon of Vinyl Halides with an Intramolecular Thiol Moiety: Synthesis of Thio-heterocycles.CHEMINFORM, Issue 51 2009Mao-Yi Lei Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Catalytic Direct-Type Substitution Reaction of ,-Alkyl Enolates: A Pd/Broensted Base Catalyzed Approach to the Decarboxylation Allylation of Sulfonylimidates.CHEMINFORM, Issue 17 2009S. B. Jennifer Kan Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A New Approach to Anodic Substitution Reaction Using Acoustic Emulsification.CHEMINFORM, Issue 41 2008Ryosuke Asami Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Copper-Catalyzed ,-Selective and Stereospecific Substitution Reaction of Allylic Carbonates with Diboron: Efficient Route to Chiral Allylboron Compounds.CHEMINFORM, Issue 13 2006Hajime Ito Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthetic Studies on 3-Arylquinazolin-4-ones: Intramolecular Nucleophilic Aromatic Substitution Reaction of 2-Carboxamido-3-arylquinazolin-4-ones and Its Application to the Synthesis of Secondary Aryl Amines.CHEMINFORM, Issue 33 2005Haruhiko Fuwa Abstract For Abstract see ChemInform Abstract in Full Text. [source] Cobalt-Catalyzed Allylic Substitution Reaction of Allylic Ethers with Phenyl and Trimethylsilylmethyl Grignard Reagents.CHEMINFORM, Issue 49 2004Keiya Mizutani No abstract is available for this article. [source] Stereoselective Synthesis of 1,4-Bifunctional Compounds by Regioselective Pd-Catalyzed Allylic Substitution Reaction.CHEMINFORM, Issue 41 2004Naoyoshi Maezaki Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Novel Mannich-Type Nucleophilic Substitution Reaction with Tertiary Aromatic Amines.CHEMINFORM, Issue 30 2002Hiroyasu Takahashi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Stereoselective Synthesis of Chiral Amino Allenes by Organocopper-Mediated anti-SN2,-Substitution Reaction of Chiral Ethynylaziridines.CHEMINFORM, Issue 14 2001Hiroaki Ohno Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Highly Regio- and Stereo-Controlled Pd(0)-Catalyzed Nucleophilic Substitution Reaction for the Synthesis of Optically Active ,-Fluoroalkylated Allylic Alcohols.CHEMINFORM, Issue 4 2001Tsutomu Konno Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Boomerang-Type Substitution Reaction: Reactivity of Fullerene Epoxides and a HalofullerenolCHEMISTRY - AN ASIAN JOURNAL, Issue 2 2007Zhenshan Jia Abstract The Cs -symmetric fullerene chlorohydrin C60(Cl)(OH)(OOtBu)4 reacts with 4-dimethylaminopyridine (DMAP) and 1,4-diazabicyclo[2.2.2]octane (DABCO) to yield two isomers with the formula C60(O)(OOtBu)4 in good yields. These isomers differ with respect to the location of the epoxy functionality. The one from DMAP is Cs symmetric, whereas that from DABCO is C1 symmetric with the epoxy group on the central pentagon. Two different mechanisms are proposed to explain the chemoselectivity of these reactions. The reaction with DMAP involves single-electron transfer as the key step; DMAP acts as the electron donor. A combination of an oxygen-atom shift and SN2,, processes (boomerang substitution) are responsible for the formation of isomer with DACBO. Various related reactions support the proposed mechanisms. The structures of new fullerene derivatives were determined by spectroscopy, single-crystal X-ray analysis, and chemical correlation experiments. [source] Synthesis of Cyclopropane-containing Building Blocks via Ir-Catalyzed Enantioselective Allylic Substitution Reaction,CHINESE JOURNAL OF CHEMISTRY, Issue 9 2010Jibao Xia Abstract Chiral cyclopropane-containing building blocks, which are very important synthetic intermediates for natural products or pharmaceuticals, were easily synthesized via Ir-catalyzed enantioselective allylic substitution reaction. [source] Nucleophilic Substitution Reaction of p -Dinitrobenzene by a Carbanion: Evidence for Electron Transfer MechanismCHINESE JOURNAL OF CHEMISTRY, Issue 11 2002You-Cheng Liu Abstract On the basis of investigation of cyclic voltammetry, EPR spectroscopy and competition experiments, the nucleophilic substitution reaction of p - dinitrobenzene with the sodium salt of ethyl ,-cyanoacetate carbanion in dimethyl sulfoxide giving ethyl ,-cyano-,- (p-nitrophenyl) acetate is shown to take place via the intermediacy of p -dinitrobenzene radical anion. The reaction rate goes faster than that between p -nitrohalobenzenes and the same sodium salt of ethyl ,-cyanoacetate carbanion. There is an evidence for a single electron transfer mechanism. [source] Nucleophilic Substitution Reactions of meso -5,10,15-Tris(pentafluorophenyl)corrole; Synthesis of ABC-Type Corroles and Corrole-Based OrganogelsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2010Takaaki Hori Abstract Nucleophilic substitution reactions of 5,10,15-tris(pentafluorophenyl)corrole (1) with amines were examined as a post-modification route to functional corroles. Reaction of 1 with an excess of amine nucleophiles led to exclusive formation of 5,10,15-tris(4-amino-2,3,5,6-tetrafluorophenyl)-substituted corroles. In this nucleophilic reaction, 5- and 15-pentafluorophenyl substituents were found to be more reactive than the substituent at the 10-position. This substitution reaction was applied for the preparation of ABC-type corroles and corrole-based organogels. The latter exhibited a blue-shifted Soret band and small fluorescence quantum yields in nonpolar hydrocarbon solvents due to the formation of H-type aggregates. [source] Theoretical Description of Substituent Effects in Electrophilic Aromatic Substitution ReactionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 35 2008Tobias Schwabe Abstract The ability of the current Kohn,Sham density functional theory (DFT) to compute the change of the proton affinity (PA) of phenol derivatives due to substitution is investigated. These systems can be used as models to predict reactivities in electrophilic aromatic substitution reactions. The complexity of the problem is increased systematically by introducing successively up to four substituents in five typical cases (methyl, cyano, fluorine, chlorine, and bromine). Our investigation can be regarded as representative for an important class of problems consistently encountered in the DFT modeling of organic reactions. High-level theoretical reference data from CCSD(T) and SCS-MP2 wave-function calculations are presented, and the PAs are compared to those obtained by a series of density functionals (DFs). It is shown that not all DFs are capable of quantitatively reproducing the substituent effects. These can be simply linear in the number of substituents or show more complicated patterns. Especially for halogens, some DFs even fail completely. In these cases, linearly increasing errors with the number of groups are observed. Reliable results are obtained with hybrid DFs or the even more accurate double-hybrid DF approach. The errors are attributed to the common self-interaction (over-delocalization) error in part of the DFs. Comparison with Hartree,Fock results shows that a reliable account of electron correlation is necessary to compute the PA of unsaturated and highly substituted molecules with chemical accuracy.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Thermodynamic Study of ,H Complexes in Nucleophilic Aromatic Substitution Reactions: Relative Stabilities of Electrochemically Generated RadicalsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2008Iluminada Gallardo Abstract The mechanism for the electrochemical oxidation of ,H complexes, such as 1-hydro-1-alkoxy/sulfoxy or -fluoro-2,4-dinitro/2,4,6-trinitrocyclohexadienyl anions, has been widely studied by means of cyclic voltammetry and controlled-potential electrolysis. Previous studies have shown that the electrochemical oxidation of ,H complexes, formed by the addition of carbon or nitrogen nucleophiles followed by a two electron mechanism, corresponding to the formal elimination of the hydride anion (nucleophilic aromatic substitution of hydrogen mechanism, the NASH mechanism). For these ,H complexes (Nu, = OH,, ,OR, ,SR, ,F), the electrochemical reaction takes place by a one-electron mechanism and is followed by the radical elimination of the leaving group with the consequent recovery of the starting material. This mechanism is similar to that proposed for the electrochemical oxidation of ,X complexes (nucleophilic aromatic substitution of a heteroatom, the NASX mechanism). The operating mechanism in each case, the NASH or NASX, can be rationalized in terms of thermodynamics. The standard potentials of the , complex and/or the leaving group as well as the bond dissociation energies (BDEs) are determinant factors. This study has not led to a significant improvement in the electrochemical preparation of aromatic-substituted compounds, but does help to understand and predict the usefulness or uselessness of using the nucleophilic aromatic substitution route to obtain a desired product. Finally, the current approach extends the electrochemical methodology to different chemical fields, for example, to general nondestructive methods for the detection, identification, and quantification of either organic pollutants or explosives in different solvents. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Preparation of Chiral Homoannularly Bridged N,P-Ferrocenyl Ligands by Intramolecular Coupling of 1,5-Dilithioferrocenes and Their Application in Asymmetric Allylic Substitution Reactions,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 33 2007Shin-ichi Fukuzawa Abstract Homoannularly bridged ferrocene 6b was prepared by intramolecular coupling of 1,5-dilithioferrocene 5b mediated by Fe(acac)3. Dilithioferrocene 5b was prepared by lithium,halogen exchange of the corresponding diiodide, which was prepared by 1,5-dilithiation of the o -TMS-blocked ferrocene and followed by trapping with iodine and removal of the TMS group. Alternatively, 5b could be readily prepared by the reaction of o -bromophenylferrocene 8 with nBuLi (>2 equiv.). The benzene ring of 6b underwent ortho lithiation with tBuLi, and the resulting lithiated species was trapped with Ph2PCl to produce corresponding aminophosphane 7d. Aminophosphane 13, which has the phosphanyl group on the cyclopentadienyl ring, was prepared by intramolecular coupling of 1,5-dilithiated PhPPFA 11 mediated by Fe(acac)3. New N,P ligands 7d and 13 were used in the palladium-catalyzed allylic alkylation and amination of 1,3-diphenyl-2-propenyl acetate (14), and ligand 7d was found to give good yields with enantioselectivities as high as 96,% ee. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Pyranoside Phosphite-Oxazoline Ligand Library: Highly Efficient Modular P,N Ligands for Palladium-Catalyzed Allylic Substitution Reactions.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009A Study of the Key Palladium Allyl Intermediates Abstract We have screened a library of modular phosphite-oxazoline ligands for asymmetric allylic substitution reactions. The library is efficiently prepared from the commercially available and cheap D -glucosamine. The introduction of a phosphite moiety into the ligand design is highly advantageous for the product outcome. Therefore, this ligand library affords good-to-excellent reaction rates [TOFs up to 600 mol substrate×(mol Pd×h),1] and enantioselectivities (ees up to 99%) and, at the same time, shows a broad scope for mono-, di- and trisubstituted linear hindered and unhindered substrates and cyclic substrates. The NMR studies on the palladium allyl intermediates provide a deeper understanding about the effect of the ligand parameters on the origin of enantioselectivity. [source] Modular Furanoside Phosphite-Phosphoroamidites, a Readily Available Ligand Library for Asymmetric Palladium-Catalyzed Allylic Substitution Reactions.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009Origin of Enantioselectivity Abstract A library of furanoside phosphite-phosphoroamidite ligands has been synthesized and screened in the palladium-catalyzed allylic substitution reactions of several substrate types. These series of ligands can be prepared efficiently from easily accessible D -xylose and D -glucose. Their modular nature enables the position of the phosphoroamidite group, configuration of C-3 of the furanoside backbone and the substituents/configurations in the biaryl phosphite/phosphoroamidite moieties to be easily and systematically varied. By carefully selecting the ligand components, therefore, high regio- and enantioselectivities (ees up to 98%) and good activities have been achieved in a broad range of mono- and disubstituted hindered and unhindered linear and cyclic substrates. The NMR studies on the palladium-,-allyl intermediates provide a deeper understanding about the effect of the ligand parameters on the origin of enantioselectivity. They also indicate that the nucleophilic attack takes place predominantly at the allylic terminal carbon atom located trans to the phosphoroamidite moiety. [source] New Carbohydrate-Based Phosphite-Oxazoline Ligands as Highly Versatile Ligands for Palladium-Catalyzed Allylic Substitution ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 15 2005Yvette Mata Abstract We have designed and synthesized a new family of readily available phosphite-oxazoline ligands for Pd-catalyzed asymmetric allylic substitution reactions. These ligands can be tuned in two regions to explore their effect on catalytic performance. By carefully selecting the ligand components, we obtained high enantioselectivities in the Pd-catalyzed allylic substitution in substrates with different steric properties [source] Modular Furanoside Diphosphite Ligands for Pd-Catalyzed Asymmetric Allylic Substitution Reactions: Scope and LimitationsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Montserrat Diéguez Abstract We have synthesized a library of furanoside diphosphite ligands for the Pd-catalyzed allylic substitution reactions of acyclic and cyclic allylic esters. The library has been designed to rapidly screen the ligands to uncover their important structural features and to determine the scope of diphosphite ligands in these catalytic reactions. After the systematic variation of the sugar backbone, the substituent at C-5 and the phosphite moieties, the diphosphite ligand 4c was found to be optimal in the Pd-catalyzed asymmetric allylic substitution of hindered (S1) and unhindered (S2,S5) substrates, yielding high activities [TOFs up to >3000,mol×(mol×h),1] and enantioselectivities (ees up to 99%). In addition, the screening of the library enabled us to find other suitable ligands for hindered disubstituted linear substrate S1 (ligands 1b,d, g and 4b, d, g) and for unhindered cyclic substrates S3,S5 (ligands 6c and 7c). [source] ChemInform Abstract: Copper(I)-Catalyzed Substitution Reactions of Propargylic Amines: Importance of C(sp),C(sp3) Bond Cleavage in Generation of Iminium Intermediates.CHEMINFORM, Issue 33 2010Tsuyuka Sugiishi Abstract Substitution reactions of propargylic amines using various secondary amines proceed in the presence of a copper(I) catalyst. [source] ChemInform Abstract: Indium Triflate-Assisted Nucleophilic Aromatic Substitution Reactions of Nitrosobenzene-Derived Cycloadducts with Alcohols.CHEMINFORM, Issue 24 2010Baiyuan Yang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: tert-Alcohol-Functionalized Imidazolium Ionic Liquid: Catalyst for Mild Nucleophilic Substitution Reactions at Room Temperature.CHEMINFORM, Issue 10 2010Sandip S. Shinde Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: From DMF to Isatin: A Novel and General One-Pot Synthesis of Isatin and Its N-Unsubstituted Derivatives via Nucleophilic Substitution Reactions on 1,2-Bis(dimethylamino)-1,2-dichloroethene.CHEMINFORM, Issue 41 2009Stefan M. Huber Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Iodine-Catalyzed C- and O-Nucleophilic Substitution Reactions of Aryl-Propargyl Methanols.CHEMINFORM, Issue 8 2008P. Srihari Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Copper-Catalyzed Substitution Reactions of Acylal with Organomanganese Reagents.CHEMINFORM, Issue 39 2007Madhukar B. Deshmukh Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] | |||||||||||||||||||||||||||||||