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Showing 1 to 20 of 48 for “"nucleophilic addition"”.
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Intermediates and Mechanisms of Gold(I)-Catalyzed Nucleophilic Addition Reactions
… of alkenes, alkynes and allenes to initiate nucleophilic addition reactions. As the key intermediates in these reactions, there has been recent interest in the synthesis and study of cationic, two-coordinate gold pi-hydrocarbon complexes. However, few experimental studies have been focused on …
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The importance of the antiperiplanar effect in the nucleophilic addition of hydride to a carbonyl group.
We have measured the relative rates for addition of lithium aluminum hydride, sodium borohydride and triethylsilane to the conformationally fixed ketone 44 and its $\alpha$-methyl, -methylthio, -methoxy, -chloro and -fluoro quasi-axial and quasi-equatorial derivatives 45-53. On the basis of a …
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Nucleophilic Addition to Azoalkenes; Diastereoselective Synthesis of β-Hydroxy Ketones and β,γ-Fused γ-Lactams
… of ketones and their derivatives by the addition of their corresponding enolates to alkyl halides is a fundamental synthetic transformation, but its utility is limited because the key bond-forming step proceeds in a bimolecular nucleophilic substitution fashion. Here in the first part of …
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Amine Nucleophilic Addition to Nitro-alkene as a New Reaction Mode for the Synthesis of N-heterocycles
Amine Nucleophilic Addition to Nitro-alkene as a New Reaction Mode for the Synthesis of N-heterocycles: An efficient stereoselective synthesis of polycyclic lactams has been developed using Michael addition of conjugated amino-esters to nitro-alkenes. Using acyclic and cyclic aminoesters, this …
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I. Multicatalysis: Development of a BiOTf₃-catalyzed Nucleophilic Addition/Hydrofunctionalization Reaction in the Synthesis of Complex Heterocycles; . . .
… was part of a multicatalytic strategy combining nucleophilic additions to aliphatic aldehydes and N-tosyl imines to quickly generate complex 5-membered heterocycles in moderate to good diastereoselectivity. The palladium-pivalate catalytic system has emerged as one of the most efficient and …
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Addition Reactions or Diethyl 2,4-dicyanoglutaconate
… is generally brought about by a base-catalyzed, nucleophilic addition. The purpose of this work is to investigate and to evaluate the applicability of the readily-available diethyl 2,4-dicyanoglutaconate in a similar type of reaction. Such a reaction, if feasible, would permit the introduction of …
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Lithiation of Alkyl 2,6-Substituted Benzoates Adjacent to Oxygen: Alpha-Lithioalkyl Alcohol Synthons
… to select structures in which proton removal and nucleophilic addition to the ester carbonyl are not competitive with metalation.
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Synthesis of N-alkyl-and N,N-dialkyl-N'-acyl- and N'-aroythioureas, and aspects of their co-ordination chemistry with Pt(II)and Pd(II)
… or aroyl isothiocyanate. This synthesis requires nucleophilic addition of the amine to the thiocarbonyl carbon of the acyl or aroyl isothocyanate. However, a competitive side-reaction frequently occurs because the amine nucleophile can attack the carbonyl carbon of the isothiocyanate reagent …
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Enantioselective synthesis of 2,2,5-Tri- and 2,2,5,5-tetrasubstituted tetrahydrofurans and synthesis of diketopiperazine containing natural products
… highly diastereoselective Diels−Alder cycloadditions with various substituted furans in excellent yield. The cycloadducts can be stereoselectively transformed into tetrasubstituted tetrahydrofurans via ring-opening metathesis/cross-metathesis or oxidative cleavage and refunctionalization. A …
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Characterizations of Gold Complexes and Mechanism of its Usage in π-bond Activation Reactions
… in π-bond activation reactions to initiate nucleophilic addition. But experimental studies focused on gold heteroatom π-complexes were still limited. It is significant to research on the intermediates involved in gold-catalyzed reactions. Many groups have studied methodology and …
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Synthesis of nitrogen heterocycles via the intramolecular [4+2] cycloaddition of iminoacetonitriles
… effect. The substrates for these [4+2] cycloadditions are prepared from readily available alcohols via a Mitsunobu reaction with the previously unknown N-cyanomethyltriflamide (HN(Tf)CH₂CN) followed by cesium carbonate promoted elimination of trifluoromethanesulfinate. The a-amino nitrile …
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Photochemical, photophysical, and photobiological studies of zeolite guest-host complexes
… electron transfer chemistry in the absence of a nucleophilic addition reaction with the electron donor. In a second example, ketoprofen (a non-steroidal anti-inflammatory drug) was found to undergo intrazeolite photodecarboxylation to generate a benzylic carbanion. The lifetime of the …
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Phosphorus-Stabilized, Carbanion-Accelerated Claisen Rearrangements: Asymmetric Induction via 1,3,2-Oxazaphosphorinanes
… allyl vinyl ethers are synthesized by the nucleophilic addition of allyloxides to phosphorus-substituted allenes, which are obtained in one step from simple starting materials. The phosphorus-stabilized, carbanion-accelerated Claisen rearrangements proceed rapidly at room temperature in …
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A COMPUTATIONAL STUDY ON BIOCHEMICAL REACTIONS OF SULFUR-CONTAINING COMPOUNDS
… DNA methylation by the DNA methyltransferase via nucleophilic addition of a Cysteine thiol and methyl transfer from SAM to cytosine; (2) H2S release from the reaction of a free thiol and garlic-derived organosulfur compounds. The thesis has 7 main chapters. Chapter 1 introduces the two …
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Part 1. Diaziridinium Ions: First Reported Synthesis and Reactivity Studies. Part 2. Tropylium Ion Mediated alpha-Cyanation of Amines. Part 3. Multicatalytic Synthesis of Complex Tetrahydrofurans
… that uses bismuth(III) triflate to catalyze a nucleophilic addition to an aldehyde followed by hydroalkoxylation to generate highly functionalized tetrahydrofuran rings, a motif that is often encountered in natural product architectures.
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El lenguaje químico en la resolución de problemas sobre reactividad en química orgánica: un estudio de casos
… language, problem solving, meaningful learning, nucleophilic addition, organic chemistry.
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The Chemistry of Cyclopropylarene Radical Cations
… cyclopropane ring opening nor deprotonation but nucleophilic addition. Side-chain oxidation products from Ce(IV) oxidation of methylated anthracenes arose from further reaction of nuclear oxidation products under acidic and higher temperature conditions. An analogous (more product-like) …
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The Reactivity of Ditetrelenes Towards Organophosphorus Oxides
… with ditetrelenes 4 and 5 resulted in a 1,3-addition to form diorganodisilyl and digermyl phosphinites 27, 28, 31, 32 and disilyl phosphites 35 and 36. The 1,3-addition resulted in a mild two electron reduction of the P(V) centre of the phosphine oxide and phosphite to a P(III) centre in the …
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Sulfoxide Catalyzed Dehydrative Glycosylation. Reaction Development and Mechanistic Analysis
… for the coupling of carbohydrate hemiacetals and nucleophilic alcohols has been developed. In this procedure, a glycosyl hemiacetal is treated with the reagent combination of benzenesulfonic anhydride and a substoichiometric amount of n-butyl sulfoxide, followed by the addition of an appropriate …
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Synthesis and reactivity of alpha-thio-beta-chloroacrylamides and alpha-thio-beta-chloroenones
… compounds, the key transformations included nucleophilic additions and Stille cross-coupling at the β-carbon. Chapter 1 reviews the literature relevant to the research conducted, and focuses in particular on the synthesis of β-chloroenones and related unsaturated carbonyl compounds. The …
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