The Diels-Alder Diene Synthesis.

Norton, James A.

doi:10.1021/cr60099a003

Cited by 122 publications

(47 citation statements)

References 147 publications

(243 reference statements)

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“…We have started this study as part of an exploratory program of the potential of controlling reactivity patterns by oriented EEFs, [1,2] and chose to focus here on the DA reaction as a candidate for EEF catalysis, because of its immense importance in chemistry [3] and its impact on mechanistic thinking ever since its discovery in the 1920s. [4][5][6] Indeed, the DA reaction has become a chemical icon, because of its unrivaled applicability and deep conceptual implications.…”

Section: Introductionmentioning

confidence: 99%

Oriented Electric Fields Accelerate Diels–Alder Reactions and Control the endo/exo Selectivity

et al. 2010

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Herein we demonstrate that an external electric field (EEF) acts as an accessory catalyst/inhibitor for Diels-Alder (DA) reactions. When the EEF is oriented along the "reaction axis" (the coordinate of approach of the reactants in the reaction path), the barrier of the DA reactions is lowered by a significant amount, equivalent to rate enhancements by 4-6 orders of magnitude. Simply flipping the EEF direction has the opposite effect, and the EEF acts as an inhibitor. Additionally, an EEF oriented perpendicular to the "reaction axis" in the direction of the individual molecule dipoles can change the endo/exo selectivity, favouring one or the other depending on the positive/negative directions of the EEF vis-à-vis the individual molecular dipole. At some critical value of the EEF along the "reaction axis", there is a crossover to a stepwise mechanism that involves a zwitterionic intermediate. The valence bond diagram model is used to comprehend these trends and to derive a selection rule for EEF effects on chemical reactions: an EEF aligned in the direction of the electron flow between the reactants will lower the reaction barrier. It is shown that the exo/endo control by the EEF is not associated with changes in secondary orbital interactions.

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Section: Introductionmentioning

confidence: 99%

Oriented Electric Fields Accelerate Diels–Alder Reactions and Control the endo/exo Selectivity

et al. 2010

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“…No depression in m.p. was observed on admixing with authentic isodurenol (7), and the i.r. and p.nl.r.…”

Section: Preparatiotl Of Lf It1 the Presetrce Of Lewis Acidmentioning

confidence: 94%

Influence of Lewis acids on the Diels–Alder reaction. II. Rearrangement of 1- and 1,4-substituted diethyl 7-oxabicyclo[2•2•1]2,5-heptadiene-2,3-dicarboxylate adducts to 4- and 4,6-substituted diethyl 3-hydroxyphthalates

Mcculloch¹,

Stanovnik²,

Smith³

et al. 1969

Can. J. Chem.

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Direct formation of 4-or 4,6-alkyl and aryl substituted diethyl 3-hydroxyphthalates from the correspondingly substituted Diels-Alder adducts of 2-or 2,5-substituted fi~rans and diethyl acetylenedicarboxylate is pronloted by AICI, in CH2C12 at room temperature. The first adduct of 2,5-diphenylfuran to be isolated has been obtained from the same reaction at -20'. The aromatic compounds can be obtained alternatively by treating the adducts with BF, or H2S04: where the adducts can be prepared by conventional means this two-step procedure has resulted in greatly improved yields. Adducts of furan and furfuryl alcohol are similarly converted to substituted phenols. HCI effected conversion only in the case of adducts carrying a bridgehead aryl substituent; in all other cases HCI added to the substituted double bond. The mechanism of the adduct rearrangement is discussed.

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“…[41,42] In addition to CO 2 , biomass is regarded as a renewable, abundant, and attractive carbon-based feedstock as well as a promising alternative for fossil sources. However, compared with benzaldehyde, the presence of the furan ring in furfural and HMF makes them more reactive and unstable, and various complicated furan ringrelated reactions such as Diels-Alder reaction, [49] hydrolytic ring opening, [50] hydrogenolytic ring opening, [51] ring hydrogenation, [52] furan ring polymerization, [53,54] and humin formation [55,56] were observed during their transformations. [44,45] In addition, both furfural and 5hydroxymethylfurfural (HMF) are biomass-based versatile platform chemicals with high potential for the syntheses of biofuels and biomass-based fine chemicals such as levulinic acid, [46,47] γ-valerolactone, 3,5-dihydroxymethylfurfural, 2,5-furandicarboxylic acid, 2,5-diformylfuran, and so on.…”

Section: Introductionmentioning

confidence: 99%

“…[48] We thus believe it should be very promising in terms of green chemistry and high atom efficiency to investigate a four-component coupling reaction by using renewable building blocks of CO 2 and biomassbased furfural or HMF for the preparation of furyl-containing 1,3-oxazolidin-2-ones. However, compared with benzaldehyde, the presence of the furan ring in furfural and HMF makes them more reactive and unstable, and various complicated furan ringrelated reactions such as Diels-Alder reaction, [49] hydrolytic ring opening, [50] hydrogenolytic ring opening, [51] ring hydrogenation, [52] furan ring polymerization, [53,54] and humin formation [55,56] were observed during their transformations. Furthermore, the presence of an activated hydroxymethyl group in HMF makes it more difficult to become the desired product.…”

Section: Introductionmentioning

confidence: 99%

Copper(I)‐Catalyzed Four‐Component Coupling Using Renewable Building Blocks of CO₂ and Biomass‐Based Aldehydes

Chen

Guo

et al. 2018

Eur J Org Chem

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Both carbon dioxide‐ (CO2) and biomass‐based molecules have recently been regarded as renewable, abundant, environmentally benign, and attractive carbon feedstocks for organic synthesis. Therefore, a mild and efficient method for the synthesis of 1,3‐oxazolidin‐2‐ones was developed through a “green” four‐component coupling reaction by using CO2, biomass‐based aldehydes such as furfural and 5‐hydroxymethylfurfural (HMF), terminal aromatic alkynes, and primary aliphatic amines with copper iodide as a catalyst. 24 Furyl‐substituted 1,3‐oxazolidin‐2‐ones were obtained in 29–84 % yield from the four‐component coupling reaction. Moreover, the coupling reaction was applicable to the syntheses of furyl‐containing bisoxazolidinone and polyoxazolidinone under mild conditions.

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The Diels-Alder Diene Synthesis.

Cited by 122 publications

References 147 publications

Oriented Electric Fields Accelerate Diels–Alder Reactions and Control the endo/exo Selectivity

Oriented Electric Fields Accelerate Diels–Alder Reactions and Control the endo/exo Selectivity

Influence of Lewis acids on the Diels–Alder reaction. II. Rearrangement of 1- and 1,4-substituted diethyl 7-oxabicyclo[2•2•1]2,5-heptadiene-2,3-dicarboxylate adducts to 4- and 4,6-substituted diethyl 3-hydroxyphthalates

Copper(I)‐Catalyzed Four‐Component Coupling Using Renewable Building Blocks of CO₂ and Biomass‐Based Aldehydes

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The Diels-Alder Diene Synthesis.

Cited by 122 publications

References 147 publications

Oriented Electric Fields Accelerate Diels–Alder Reactions and Control the endo/exo Selectivity

Oriented Electric Fields Accelerate Diels–Alder Reactions and Control the endo/exo Selectivity

Influence of Lewis acids on the Diels–Alder reaction. II. Rearrangement of 1- and 1,4-substituted diethyl 7-oxabicyclo[2•2•1]2,5-heptadiene-2,3-dicarboxylate adducts to 4- and 4,6-substituted diethyl 3-hydroxyphthalates

Copper(I)‐Catalyzed Four‐Component Coupling Using Renewable Building Blocks of CO2 and Biomass‐Based Aldehydes

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Copper(I)‐Catalyzed Four‐Component Coupling Using Renewable Building Blocks of CO₂ and Biomass‐Based Aldehydes