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Oxidative cycloadditions

To illustrate the overall magnitude of the mechanistic problem, let us consider the varied reactivity of a prototypical carbonyl compound such as acetone, which is subject to many diverse reactions such as addition, substitution, cycloaddition, oxidation, reduction, etc., as illustrated in Chart 2. [Pg.195]

When propargylamine 183 was subjected to a homologative allenylation (Crabbe reaction) at 100 °C, the resulting allene underwent a spontaneous Diels-Alder reaction to give the adduct 184. This intramolecular cycloaddition-oxidation sequence provided a simple route to indole alkaloids such as hippadine and ds-trikentrin B [148]. [Pg.786]

Zugravescu et al. have reacted the quinoxaline ylid 455 with DMAD and obtained the 1,3-cycloaddition-oxidation product 456.433 They also claim the preparation of 461 from quinoxaline di-JV-oxide (460),434 but isomeric structures do not seem excluded. The quinoxaline imine 457 with DMAD and EP gives 458 and 459, respectively.431... [Pg.419]

Ethyl-2-(sulfonylmethyl)- and 2-(cyanomethyl)-allyl carbonates133 as well as (methoxycarbo-nyl)methylallyl carbonates136 serve as substrates for the [3 + 2] cycloaddition. Oxidative addition into the allylic C—O bond of the carbonate, followed by decarboxylation, gives a 2-substituted allylpalladium al-koxide. The alkoxide then deprotonates the C—H a to the electron-withdrawing substituent at the 2-position of the allyl. This anion then undergoes a Michael addition to an a,(3-unsaturated ketone or ester, followed by intramolecular allylation of the anion of the Michael product (Scheme 2). [Pg.593]

The DFT study of the 3 + 2-cycloaddition between ketene and TV-silyl-, IV-germyl-, and TV-stannyl-imines shows that the TV-germylimine reaction is a two-step process the TV-stannylimine reaction is a competition between two- and three-step processes whereas the TV-silyl process follows a three-step process44 A new and convenient synthesis of functionalized furans and benzofurans based on 3 + 2-cycloaddition/oxidation has been reported. The cyclization of cyclic 1,3-bis-silyl enol ethers (48) with l-chloro-2,2-dimethoxyethane (49), via a dianion, produced 5,6-bicyclic 2-alkylidenetetrahydrofurans (50), which are readily oxidized with DDQ to 2,3-unsubstituted benzofurans (51) (Scheme 13)45 The Evans bis(oxazoline)-Cu(II) complex catalyses the asymmetric 1,3-dipolar cycloaddition of a -hydroxyenones with nitrones to produce isoxazolidines.46 The... [Pg.357]

During the past decade, many different examples of one- and two-coordinate, trivalent phosphorus compounds have been synthesized and isolated as thermally stable, but chemically reactive, products. The two-coordinate derivatives, in particular, have been found to undergo a variety of interesting and synthetically useful transformations, a few of which are illustrated below. Although several examples of addition, cycloaddition, oxidation, and metal-coordination reactions of two-coordinate phosphines are readily found in the literature (7), there is still a great deal of work to be done before the full potential of these new reagents can be realized. [Pg.76]

Scheme 5 Asymmetric [3+2] cycloaddition/oxidation of azomethine ylides with quinones... Scheme 5 Asymmetric [3+2] cycloaddition/oxidation of azomethine ylides with quinones...
One important visible-light-induced C-H oxidation/[3 + 2] cycloaddition/ oxidative aromatization tandem sequence was developed by Xiao and co-workCTS in 2011, allowing for concise synthesis of pyrrolo[2,l-a]isoquinolines (Scheme 3.7) [35]. [Pg.75]

Scheme 3.7 Visible-light-induced C-H oxidation/[3 + 2] cycloaddition/oxidative aromatization sequence [35]... Scheme 3.7 Visible-light-induced C-H oxidation/[3 + 2] cycloaddition/oxidative aromatization sequence [35]...
Zou Y-Q, Lu L-Q, Fu L, Chang N-J, Rong J, Chen J-R, Xiao W-J (2011) Visible-Ught-induced oxidation7[3+2] cycloaddition/oxidative aromatization sequence a photocatalytic strategy to construct pyrrolo[2,l-a]isoquinolines. Angew Chem Int Ed 50 7171-7175... [Pg.392]

Spiroacetals have been found to be a common motif in complex natural products and as such are a popular synthetic target. The need to synthesize these scaffolds in a selective and efficient manner has driven efforts to develop new methods for their synthesis. A wide variety of techniques have emerged, including dehydrative methods, cycloadditions, oxidative methods, reductive couplings, ring-opening... [Pg.262]

In chapter entitled Synthesis of Substituted Tetrahydrofurans, J. D. Rainier outlines the advances that have been made during the last 10 years in the synthesis of tetrahydrofurans such as nucleophilic additions to acetals and hemiacetals, cycloadditions, oxidative cyclizations, furan reductions, Prins-pinacol cascades, ring-opening of bicyclic substrates, and nucleophilic substitutions. [Pg.287]

A one-pot domino Claisen-Schmidt/l,3-dipolar cycloaddition/oxidation reaction sequence involving an aldehyde (801), a methyl ketone (802), and the Bestmann Ohira reagent (803), has been developed for the synthesis of variously substituted 3-carbo-5-phosphonylpyrazoles (804) (Scheme 204). ... [Pg.175]

Scheme 11.18) [39]. The five-step sequence (cycloaddition, oxidation, ester hydrolysis, carbonyl deprotection, decarboxylation) required for the transformation of chromium carbene chelate 50 into the benzyl-protected rolipram precursor has been performed tvithout isolation of any intermediates after the final debenzyla-tion (-I-)-rolipram 51 is obtained in lotv overall yield. [Pg.462]


See other pages where Oxidative cycloadditions is mentioned: [Pg.62]    [Pg.72]    [Pg.179]    [Pg.396]    [Pg.383]    [Pg.228]    [Pg.233]    [Pg.158]   
See also in sourсe #XX -- [ Pg.21 , Pg.22 ]

See also in sourсe #XX -- [ Pg.184 ]




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1,3-Dipolar cycloadditions nitrile oxides + alkenes

1,3-Oxazolium 4-oxides 1,3-dipolar cycloadditions

1,3-dipolar cycloaddition aryl nitrile oxides

1,3-dipolar cycloaddition of nitrile oxide

1,3-dipolar cycloaddition reactions aliphatic nitrile oxides

1,3-dipolar cycloaddition reactions with nitrile oxides

1.3- Dipolar cycloaddition of benzonitrile oxide

1.3- Dipolar cycloaddition reactions nitrile oxides

2/7-Pyrrole 1-oxides, 1,3-dipolar cycloaddition with DMAD

277-Pyrrole, 1-oxides, 1,3-dipolar cycloaddition

Achiral dipolarophiles, nitrile oxide cycloadditions

Acrylamides, nitrile oxide cycloadditions

Acrylates cycloaddition reactions with nitrile oxides

Adamantanethione 5-oxide cycloaddition

Aldehydes nitrile oxide intermolecular cycloadditions

Aldehydes nitrile oxide intramolecular cycloadditions

Alkenes 3+2] cycloaddition with nitrile oxide

Alkenes nitrile oxide cycloadditions

Allylic alcohols nitrile oxide cycloadditions

Aromaticity, nitrile oxide cycloadditions, dipolar

Aryl nitrile oxides, cycloaddition

Arylnitrile oxides, 1,3-dipolar cycloaddition

Asymmetric reactions nitrile oxide cycloadditions, diastereoselectivity

Azomethine oxides, cycloaddition

Azomethine oxides, cycloaddition alkynes

Benzene oxides cycloaddition reaction with singlet oxygen

Benzonitrile oxide cycloaddition

Benzonitrile oxide cycloaddition reactions

Biotin nitrile oxide intramolecular cycloadditions

By cycloaddition of nitrile oxides

Carbohydrate alkenes, nitrile oxide cycloadditions

Carbohydrate derivatives, nitrile oxide cycloadditions

Carbon oxides 2+1] cycloaddition reactions

Carbonyl compounds nitrile oxide cycloadditions

Carbonyl oxides cycloaddition

Catalytic cycloadditions nitrile oxides

Chemoselectivity, nitrile oxide cycloadditions

Chiral auxiliaries, diastereoselectivity, asymmetric nitrile oxide cycloadditions

Cycloaddition Cyclohexene oxide

Cycloaddition diene oxidation

Cycloaddition intramolecular nitrile oxide [INOC

Cycloaddition of nitrile oxides with alkenes

Cycloaddition oxidation step

Cycloaddition oxide

Cycloaddition oxide

Cycloaddition reactions diene oxidation

Cycloaddition reactions of nitrile oxides with alkenes

Cycloaddition with nitrile oxides

Cycloaddition, 1,3-dipolar diazo oxides

Cycloadditions Involving Nitrile Oxides

Cycloadditions of nitrile oxides

Cyclopentadiene, oxidative cycloaddition reaction with

Cyclopentene, oxidative cycloaddition

Diastereoselectivity nitrile oxide cycloadditions

Diisopropyl nitrile oxide cycloadditions, chiral

Dipolar cycloadditions of nitrile oxides

Dipolar cycloadditions with nitrile oxides

Dipolarophiles nitrile oxide cycloadditions

Electron-Deficient C2 Fragments (Cycloadditions Involving Azomethines, Nitrones, Nitrile Oxides, and Dienes)

Enantioselectivity nitrile oxide cycloadditions

Esters nitrile oxide cycloadditions

Facial selectivity nitrile oxide cycloadditions

Five-membered rings nitrile oxide intramolecular cycloadditions

Furans nitrile oxide intramolecular cycloadditions

Furoxans intramolecular nitrile oxide cycloadditions

Grignard reagents, nitrile oxide cycloadditions

Hole-catalyzed cycloadditions oxidation

Hydrogen bonding, nitrile oxide cycloadditions

Hydrogenation of nitrile oxide cycloaddition product

Intermolecular cycloadditions achiral nitrile oxides/chiral olefins

Intermolecular cycloadditions achiral nitrile oxides/olefins

Intramolecular nitrile oxide cycloaddition

Intramolecular nitrile oxide cycloaddition reaction

Intramolecular nitrile oxide cycloaddition synthesis

Intramolecular nitrile oxide-olefin cycloaddition

Isoxazoles, from alkenes and nitrile oxides cycloaddition

Isoxazoline compounds nitrile oxide cycloadditions

Kinetic data, nitrile oxide cycloadditions

Lactones nitrile oxide intramolecular cycloadditions

Lewis acids nitrile oxide cycloadditions

Mesitonitrile oxide cycloaddition

Mesitonitrile oxide cycloaddition reactions

Mesityl nitrile oxide, 1,3-dipolar cycloaddition

Mesityl oxide 1,3-dipolar cycloadditions

Nitric oxide cycloaddition

Nitrile oxide cycloaddition

Nitrile oxide, cycloaddition structure

Nitrile oxide, cycloaddition synthesis

Nitrile oxides 1,3-dipolar cycloadditions

Nitrile oxides cycloadditions

Nitrile oxides dipolar cycloaddition

Nitrile oxides intramolecular cycloadditions

Nitrile oxides, alkenyl intramolecular cycloaddition

Nitrile oxides, cycloaddition reactions

Nitrile oxides, cycloaddition with electron-deficient dipolarophiles

Nitrile oxides, cycloaddition with from primary nitro compounds

Nitrile oxides, cycloaddition with furoxans

Nitrile oxides, cycloadditions with alkenes

Nitrile oxides, cycloadditions, furan

Nitrile oxides, dipolar cycloaddition with

Nitrones nitrile oxide intermolecular cycloadditions

Nitrones nitrile oxide intramolecular cycloadditions

Olefins nitrile oxide cycloadditions

Oxidation, oxazole reactions 2 + 2] cycloaddition

Oxidative addition cycloadditions

Oxidative cyclization cycloaddition

Oxidative cyclizations/cycloadditions

Oxidative cyclizations/cycloadditions dimer

Oxidative cycloaddition

Oxidative cycloaddition

Oxidative cycloaddition with

Oximes nitrile oxide intramolecular cycloadditions

Radical oxidative cycloaddition

Regioselectivity nitrile oxide cycloadditions

Relative reactivity, nitrile oxide cycloadditions

Relative reactivity, nitrile oxide cycloadditions relativity

Solvent effects, nitrile oxide cycloadditions

Stereoselectivity nitrile oxide cycloadditions

Sulfur oxides 2+1] cycloaddition reactions

Thiocarbonyl 5-oxides , cycloadditions

Thiocarbonyl 5-oxides cycloaddition

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