2 edition of Quantitative studies on the addition of amine nucleophiles to Michael acceptors. found in the catalog.
Quantitative studies on the addition of amine nucleophiles to Michael acceptors.
Christina K. M. Heo
Written in English
|The Physical Object|
|Number of Pages||230|
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Michael Addition Polymerization (Conjugated Additon Reactions) The Michael addition reaction, also known as a conjugated addition, is a versatile method for the addition of various nucleophiles to (conjugated) unsaturated compounds with electron withdrawing reaction was first discovered by Arthur Michael in 1 It allows for the synthesis of a wide range of highly chemistry/Michael A series of nucleophiles, including primary and secondary amines, primary alcohols, and thiols, as well as diethyl malonate and nitromethane, were added to different fluorinated Michael acceptors For this purpose, Bernasconi reported the studies of the kinetics of the reactions of various nucleophiles such as, carbanions, amines and alkoxides towards some Michael acceptors, e.g., benzylidene Meldrum’s acids and benzylidene indandiones in DMSO/H 2 O mixtures (Bernasconi et al.,Bernasconi,Bernasconi and Panda, Review of Michael addition reactions for formation of C-X (XC=, O, N, S) bonds.
• Michael acceptors: nitroolefins, α, β-unsaturated carbonyls, imides, etc. • Organocatalysts based on ferrocene, amine, pyrrolidine, etc.
• Heterogeneous catalysts based on metal oxides. • Critical analysis and future :// Thus far, various transition metal catalysts were employed in Michael addition reactions and notable such catalysts I–IX are summarized in Scheme 1.
Ru and Cu catalyzed oxa‐and aza‐Michael addition reactions were reported. 35 Nickel pincer complexes were found to catalyze aza‐Michael addition reactions. 33, 37 Recently, Re The Michael addition reaction, the regioselective 1,4-addition of nucleophiles to activated olefins, is one of the versatile methods used for C–C, C–N bond formation, and has found wide application in organic synthesis [1,2,3,4,5,6,7,8,9,10].On the other hand, the anti-Michael or α-Michael addition reaction, the nucleophilic addition to the α-carbon of an activated olefinic compound, is This thiol/amine-triggerable chemical switch is based on a Triggerable Michael Acceptor (TMAc) which bears good leaving groups at its β-position.
The acceptor undergoes a “trigger-to-release” process where thiol/amine addition triggers cascaded release of leaving groups and generates a less activated ://#!divAbstract.
The anti‐Markovnikov addition of thiols to alkenes is usually mediated by a radical source or by UV irradiation. 76 One of the earliest systematic studies regarding the post‐polymerization modification of polyBu via radical thiol addition was reported by Serniuk et al. in 8 They proposed that only the vinyl groups generated by 1,2 The key attribute of the thiol-Michael addition reaction that makes it a prized tool in materials science is its modular “click” nature, which allows for the implementation of this highly efficient, “green” reaction in applications that vary from small molecule synthesis to in situ polymer modifications in biological systems to the surface functionalization of material coatings.
Over Strategy of Bifunctional Thiourea-tertiary Amine Catalyzed 1,6-Michael Additions of Sulfur Nucleophiles to 3-Methylnitroalkenyl-isoxazoles ARTICLE attractive 1,6-Michael acceptors,8,9i,11 and the other is that the nitro moiety of these compounds is a › 百度文库 › 高校与高等教育.
Radical-mediated lipid oxidation and the formation of lipid hydroperoxides has been a focal point in the investigation of a number of human pathologies.
Lipid peroxidation has long been linked to the inflammatory response and more recently, has been identified as the central tenet of the oxidative cell death mechanism known as ferroptosis.
The formation of lipid electrophile-protein adducts Michael addition of imidazole 7 to α-branched vinyl ketone 17 provided Michael adduct with good yield without enatioselectivity (Scheme 6).
Calvino-Casilda et al. [36 Calvino-Casilda, V.; Ba˜nares, M.A. In situ Raman monitoring of Michael addition for the synthesis of 1-substituted imidazoles intermediates with antiviral properties. :// our concept of amine-catalyzed addition of enamines formed in situ could be extended to imines as acceptors, we initially studied the reaction of acetone with a number of aromatic aldimines preformed with o-anisidine,11 thus evading concerns regarding chemoselectivity.
The three catalysts identified in our aldol studies, L-proline, 5,5- Synthesis and Stability of OND–Amine Adducts. The reactions of non-tertiary amines with ONDs were studied in closer detail to model the potential Michael addition of proteinaceous nitrogen nucleophiles (Scheme 2, Table S1).Adducts 8 and 9 were obtained from reactions of ONDs 1k and 5c with equivalents of 40% aq.
methylamine. In the former case, a ratio of syn and anti-isomers Quantitative structure–reactivity relationship studies on the catalyzed Michael addition reactions June Journal of Physical Organic Chemistry 22(6) - Mechanistic studies suggest that the addition of an conjugate addition of a broad range of mercaptan nucleophile to a very wide range of both classical and non-classical Michael acceptors An efficient palladium-catalyzed asymmetric amination of 2,3-allenyl phosphates with nitrogen nucleophiles such as amines, hydroxylamines Michael Donors.
The reactivity of different amines as Michael donor has been studied for several Michael acceptors, such as acrylates (Wu et al., ), methyl acrylates (Zou and Jiang, ), and vinyl phosphonates (Matveeva et al., ).Several factors influence the reactivity of the amine as Michael donor, such as nucleophilicity, steric hindrance, and :// Chapter 6: Hydrotrope Promoted Aza-Michael Addition Reaction Aza-Michael reaction of nucleophiles to unsaturated carbonyl compound requires basic as well as acidic conditions .
These compounds have increasing attention due to their biological activity and play an important role as intermediate in many organic Wiley-Interscience, New York, The formation of Boc-protected amines and amino acids is conducted under either aqueous or anhydrous conditions, by reaction with a base and the anhydride Boc 2 O.
Active esters and other derivatives such as Boc-ONH 2 and Boc-N 3 can also be used. The Boc group is stable towards most The detailed mechanisms for the borylation of α,β-unsaturated carbonyl compounds, acrolein and methylacrylate, catalyzed by phosphine copper(I) boryl complexes were studied with the aid of density functional theory calculations.
The results show that the catalyzed borylation occurs through C═C insertion into Cu−B to give a β-borylalkyl C-bound Cu(I) enolate :// Theoretical calculations on the Michael addition of methanethiolate anion to a series of carbonylacrylic reagents anticipated that ketoacryl esters (ΔG ≠ = kcal mol −1) and amides (ΔG ≠ = kcal mol −1) display comparable reactivity compared to maleimide (ΔG ≠= kcal mol −1), yielding quantitative product :// Chapter IV Conjugate addition of nitrogenous nucleophiles secondary as well as primary aromatic amines to almost all kinds of Michael acceptors.
H) Yttrium nitrate32 is the only economical catalyst useful in reaction between aromatic amines to a range of Michael InKomnenos reported the first conjugate addition where he added the diethyl malonate anion to ethylidene reaction was not fully investigated untilwhen Michael thoroughly studied this reaction using various stabilized nucleophiles and α,β-unsaturated of the early work, including Michael’s, involved the use of stabilized or “soft” nucleophiles In order to predict which nucleophiles 4 are suitable reagents for such transformations because they are strong enough to react with iminium ions 3, but weak enough not to react with the precursor carbonyl compounds (e.g., 2), it was necessary to determine the reactivity parameters N and s N of potential nucleophilic substrates 4 and the electrophilicity parameters E of iminium ions :// Highly Enantioselective Aza-Michael Reaction between Alkyl Amines and β-Trifluoromethyl β-Aryl Nitroolefins.
Leming Wang, Jiean Chen and Yong Huang*, Angew. Chem. Int.54, The aza-Michael addition reaction is a vital transformation for the synthesis of functionalized chiral terms in a quantitative sense.
For example, if we refer to acid strength, or acidity, this means the position of equilibrium in an acid-base reaction. The equilibrium constant Ka for the dissociation of an acid HA, or the pKa, is a quantitative measure of acid strength. The larger the value of K, or the smaller the pK, the stronger the :// amine bases 3a,b do not effect the Michael addition of less acidic pre-nucleophiles such as 4 (Scheme ).
However, the corresponding ammonium hydroxides 6a,b do promote the addition of the substrates 4 to methyl vinyl ketone under the same mild conditions, albeit with enantioselectivity not exceeding ca 40 (No Transcript) 41 (No Alkynyl ketones are attractive yet challenging nucleophiles due to their intrinsic susceptibility to Michael additions and the difficulty of controlling the enolate geometry.
Nonetheless, this method produces β-amino ynones with excellent chemo- diastereo- and enantioselectivity, and the products can be transformed into a broad range of ?f[genre_ssim]=Thesis/Dissertation&f[stanford_dept.
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However, low enzymatic stability, short half-life and low tissue permeability hamper the A single electron oxidation of an enam derived from an aldehyde 66 and a secondary amine 67 by an oxidant (typically CAN), results in the formation of the corresponding enamine radical cation Addition of nucleophiles to the a-carbon of the › 百度文库 › 实用模板.
In this paper, we assess the ability of various intrinsic molecular and atomic descriptors, grounded in the conceptual density functional theory and the quantum theory of atoms-in-molecules frameworks, to predict the electrophilicity of Michael acceptors, which are fundamental organic reagents involved in the formation of carbon–carbon :// quantitative conversion and excellent selectivity in each case (see Table 2 and the Supporting Information).
We propose the mechanism of the reaction to be a straightforward 1,4-Michael addition where remarkable observation is the formation of the thermodynamically less stable product X (nonconjugated) as compared to Y (con-Scheme :// angew chem/ The aim of this book is to cover the very recent developments in asymmetric organocatalysis, focussing on those published since the beginning of The last decade has witnessed an explosive growth in the field of asymmetric organocatalysis with an impressive amount of new catalysts, novel Low molecular weight chemical (LMW) allergens are commonly referred to as haptens.
Haptens must complex with proteins to be recognized by the immune system. The majority of occupationally related haptens are reactive, electrophilic chemicals, or are metabolized to reactive metabolites that form covalent bonds with nucleophilic centers on proteins. Nonelectrophilic protein binding may occur Page Issue in Honor of Prof.
Kessar ARKIVOC (vii) Catalytic, enatioselective Michael addition reactions S. Jha and N. Joshi* Division of Organic Synthesis, National Chemical Laboratory, Pune, India. E-mail: [email protected] Dedicated to Professor on the occasion of his 70th birthday (received 28 May 02; accepted 12 Sep 02; published on the web ?rgn=main;view=fulltext.
Catalysis plays a central role in chemistry because it allows more sustainable and environmentally friendly chemical processes Page ii Declaration This thesis is a summary of work carried out in the School of Chemistry, the University of Sydney, under the supervision of Dr.
Christopher S. Although the aza-Michael addition reaction on various unsaturated (di-)carboxylic acids and esters of, for example, itaconic acid, is well-known, the consecutive cyclization reaction has not received much attention in literature.
The products of this aza-Michael cascade reaction, being mono- or di-carboxylic acid or ester functionalized N-alkyl-pyrrolidone structures, prove interesting for 2 On the Structure of the Book, and a Few General Mechanistic Considerations 9 The Structure of the Book 9 General Mechanistic Considerations 9 References 12 3 Nucleophilic Substitution at Aliphatic Carbon 13 A-Alkylation of Cyclic Ketones and Related Compounds 13 Alkylation of &-Amino Acid Derivatives 16 Development of Highly Efficient Organocatalysts 16 Michael reactions involving nitroalkanes and enones are important carbon-carbon bond formation reactions.
These reactions are base-catalyzed, and during the past 15 years, the asymmetric version using bifunctional amino-thiourea organocatalyst has been developed.
In this work, the reaction of nitromethane and 4-phenylbutenone, catalyzed by the methoxide ion and piperidine as bases. Addition of Sulfur Nucleophiles The Wittig Reaction Forms an Alkene Stereochemistry of Nucleophilic Addition Reactions: Re and Si Faces Designing a Synthesis VI: Disconnections, Synthons, and Synthetic Equivalents Nucleophilic Addition to α, β- Unsaturated Aldehydes and KetonesThe metal‐catalysed hydrofunctionalisation of alkenes and alkynes provides a convenient and atom‐economic route to diversely functionalised products with control of regio‐, chemo‐ and stereoselectivity.
Addition of N, O and S nucleophiles to alkenes and alkynes. intermolecular reductive cross‐coupling with Michael ://This review introduces the research topic of magnesium catalysts in asymmetric synthesis.
Considering that magnesium salts are efficient catalysts in many basic chemical transformations, the design and development of novel catalytic strategies for this abundant source are highly attractive.
This review highlights the progress in this area and provides insightful discussions of the catalytic (19)