Hetero-Diels-Alder-Reaktion von 3-Aryl-2-benzoyl-2-propennitrilen mit Enolethern. Synthese von 2-Alkoxy-3,4-dihydro-2H-pyran-5-nitrilen

Bogdanowicz-Szwed, Krystyna; Pałasz, Aleksandra

doi:10.1007/bf00807566

Cited by 18 publications

(7 citation statements)

References 14 publications

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“…Although their endo / exo selectivity can not be exactly determined due to the structural nature of these substrates, such IED HDA reactions catalyzed by Eu(fod) 3 or Yb(fod) 3 are likely endo -selective according to the relevant literature. 25a–b,27 It is also reported that different coordination modes of Eu(fod) 3 and Yb(fod) 3 may account for their different facial selectivity in HDA reaction. 26 As depicted in Figure 3, the high facial selectivity induced by Yb(fod) 3 is probably ascribed to the different facial steric surrounding.…”

Section: Resultsmentioning

confidence: 99%

ent-Kaurane-based regio- and stereoselective inverse electron demand hetero-Diels–Alder reactions: synthesis of dihydropyran-fused diterpenoids

et al. 2014

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A mild and concise approach for the construction of 3,4-dihydro-2H-pyran ring integrated into the A-ring of the natural product oridonin using an optimized inverse electron demand hetero-Diels-Alder (IED HDA) reaction is reported herein. A self-dimerization of the exocyclic enone installed in the A-ring through a homo-HDA reaction was identified to exclusively give a dimeric ent-kaurane diterpenoid with the spirochroman core. Moreover, the efficient cross-HDA cycloadditions of this enone with various vinyl ethers or vinyl sulfides, instead of its own homo-HDA dimerization, were achieved in regio- and stereoselective manners, thus providing the access to novel dihydropyran-fused diterpenoids as potential anticancer agents to overcome chemoresistance.

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Section: Resultsmentioning

confidence: 99%

ent-Kaurane-based regio- and stereoselective inverse electron demand hetero-Diels–Alder reactions: synthesis of dihydropyran-fused diterpenoids

et al. 2014

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“…Such examples are cycloadditions between propenenitriles with a cyano group at C-3 of the heterodiene system [ 71 – 74 ]. Moreover, two papers [ 71 , 72 ] describe examples of cycloaddition reaction of enaminocarbaldehydes or enaminoketones with enol ethers, leading to 4-amino-3,4-dihydro-2 H -pyrans. 4-Amino-pyrans are precursors in synthesis of 3-amino sugar derivatives which are present in various antibiotics such as gentamycin C or adriamycin.…”

Section: Inverse-electron-demand Hetero-diels–alder Reactions Of 1-oxmentioning

confidence: 99%

Recent Advances in Inverse-Electron-Demand Hetero-Diels–Alder Reactions of 1-Oxa-1,3-Butadienes

Pałasz

2016

Top Curr Chem (Z)

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This review is an endeavor to highlight the progress in the inverse-electron-demand hetero-Diels–Alder reactions of 1-oxa-1,3-butadienes in recent years. The huge number of examples of 1-oxadienes cycloadditions found in the literature clearly demonstrates the incessant importance of this transformation in pyran ring synthesis. This type of reaction is today one of the most important methods for the synthesis of dihydropyrans which are the key building blocks in structuring of carbohydrate and other natural products. Two different modes, inter- and intramolecular, of inverse-electron-demand hetero-Diels–Alder reactions of 1-oxadienes are discussed. The domino Knoevenagel hetero-Diels–Alder reactions are also described. In recent years the use of chiral Lewis acids, chiral organocatalysts, new optically active heterodienes or dienophiles have provided enormous progress in asymmetric synthesis. Solvent-free and aqueous hetero-Diels–Alder reactions of 1-oxabutadienes were also investigated. The reactivity of reactants, selectivity of cycloadditions, and chemical stability in aqueous solutions and under physiological conditions were taken into account to show the potential application of the described reactions in bioorthogonal chemistry. New bioorthogonal ligation by click inverse-electron-demand hetero-Diels–Alder cycloaddition of in situ-generated 1-oxa-1,3-butadienes and vinyl ethers was developed. It seems that some of the hetero-Diels–Alder reactions described in this review can be applied in bioorthogonal chemistry because they are selective, non-toxic, and can function in biological conditions taking into account pH, an aqueous environment, and temperature.

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“…25 Also the first examples of such heterocycloadditions of allenamides and allenimides were examined. [26][27] Recently, we have reported that Diels-Alder reactions of some 3-cyano-1-oxa-1,3butadienes with enol ethers 28 or styrenes 29 lead efficiently to 2-alkoxy-3,4-dihydro-2H-pyran-5-carbonitriles. Also, we have examined the influence of cyano, carbonyl, ethoxycarbonyl groups 30 or sulfur containing substituents 31 at C-3 in 1-oxa-1,3butadienes on the intramolecular hetero-Diels-Alder reaction.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 3,4-dihydro-2H-pyrans by hetero-Diels–Alder reactions of functionalized α,β-unsaturated carbonyl compounds with N-vinyl-2-oxazolidinone

Pałasz

2005

Org. Biomol. Chem.

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Cycloadditions of 3-aryl-2-benzoyl-2-propenenitriles and 3-phenylsulfonyl-3-buten-2-one to N-vinyl-2-oxazolidinone proceed regio- and diastereoselectively yielding cis and trans diastereoisomers of 4-aryl-3,4-dihydro-2-(2-oxo-3-oxazolidinyl)-2H-pyrans in 37-65% yield. Cycloadducts cis- were the major products. Reaction of 5-arylidene-1,3-dimethylbarbituric acids with dienophile afforded mixtures of 2H-pyrano[2,3-d]pyrimidine-2,4(3H)-diones trans and products resulted from an elimination of 2-oxazolidinone, in 50-52% yield. To confirm the experimental results, semiempirical AM1 and PM3 calculations of frontier orbital energies have been performed.

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Hetero-Diels-Alder-Reaktion von 3-Aryl-2-benzoyl-2-propennitrilen mit Enolethern. Synthese von 2-Alkoxy-3,4-dihydro-2H-pyran-5-nitrilen

Cited by 18 publications

References 14 publications

ent-Kaurane-based regio- and stereoselective inverse electron demand hetero-Diels–Alder reactions: synthesis of dihydropyran-fused diterpenoids

ent-Kaurane-based regio- and stereoselective inverse electron demand hetero-Diels–Alder reactions: synthesis of dihydropyran-fused diterpenoids

Recent Advances in Inverse-Electron-Demand Hetero-Diels–Alder Reactions of 1-Oxa-1,3-Butadienes

Synthesis of 3,4-dihydro-2H-pyrans by hetero-Diels–Alder reactions of functionalized α,β-unsaturated carbonyl compounds with N-vinyl-2-oxazolidinone

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