The Ene Reaction

Hoffmann, H. M. R.

doi:10.1002/anie.196905561

Cited by 545 publications

(194 citation statements)

References 143 publications

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“…The 'H and 13C nmr spectra of la-e are entirely consistent with the structure and stereochemistry anticipated from consideration of the ene reaction mechanism (12). The cis relationship of the two ester groups is established both from the high-field chemical shift (ca.…”

Section: Adductssupporting

confidence: 76%

Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

Hanson¹,

Mcculloch²,

McInnes³

1981

Can. J. Chem.

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Can. J. Chem. 59,288 (1981). Substituted dimethyl 1,4-pentadiene-l,2-dicarboxylates (1 or 3) may be prepared by A1C13-promoted or thermal ene reaction of olefins with dimethyl acetylenedicarboxylate. Lactonization of these adducts is catalyzed by acid. In the presence of 80% H2S04 the predominant product (ca. 80%) is a (Z)-dihydro-3-carbomethoxymethylene-2(3H)-fi1ranone (2 or 4). Cyclization with anhydrous HCI affords a mixture of products, the composition of which depends on the starting material; major products include the corresponding ( a -and 6-lactone isomers (6 and 7). Detailed lH and 13C nmr data are reported for all compounds. The structures of the (a-4,5,5-trimethyl-, (a-4,5,5-trimethyl-, and (a-4,4,5,5-tetramethyl Chem. 59,288 (1981). Les pentadiene-1,4 dicarboxylates-1,2 de dimethyle substituks (1 ou 3) peuvent Ctre prepares par une reaction h e favoriske par AICI, ou par une reaction thermique des olefines avec I'acetylenedicarboxylate de dimethyle. L'acide catalyse la lactonisation de ces adduits. En presence de H2S04 2 80%, les produits majoritaires (ca. 80%) sont les (Z) dihydrocarbomCthoxymethylene-3 (3H)-furannones-2 (2 ou 4). La cyclisation par du HCI anhydre conduit a un melange de produits dont la composition depend du produit de depart; les produits principaux comprennent les isomeres (E) et les 6-lactones correspondants (6 et 7). On rapporte les donnees dCtaillees de la rmn du 'H et du 13C de tous les composes. Utilisant la diffraction des rayons-X, on a determine les structures des derives des [Traduit par le journal] IntroductionAs an extension of our studies on the effect of Lewis acids on Diels-Alder additions of dimethyl acetylenedicarboxylate (DMAD) (2), we have investigated the effect of AlCl, on ene reactions involving this compound. As anticipated, the Lewis acid causes dramatic acceleration of the reactions of DMAD with various olefins, and is particularly useful in the case of volatile olefins (see below). The adducts 1 are structurally suited as intermediates for the synthesis of substituted a-methylene-y-lactones, which are potential antitumor agents (refs. 3, 4, and references therein) and in which there has thus been considerable recent synthetic interest (5, 6). Our observation of such compounds as by-products of certain AlCl,-promoted reactions encouraged us to undertake a detailed study of the effect of acids on adducts 1.

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Section: Adductssupporting

confidence: 76%

Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

Hanson¹,

Mcculloch²,

McInnes³

1981

Can. J. Chem.

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“…It has been shown [1][2][3] that the Alder Ene reaction may be used as a method for the terminal specific maleation of polypropylene in the melt. Sufficient extent of reaction has been observed within the span of minutes compared to the more classical use of the Alder Ene reaction over a duration of hours, thus allowing its use as a means of maleating polypropylene in an extruder.…”

Section: Introductionmentioning

confidence: 99%

A parametric study of the terminal maleation of polypropylene through an Alder Ene reaction

Thompson

Tzoganakis

Rempel

1998

J. Polym. Sci. A Polym. Chem.

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“…15 The ene moiety of the Alder Ene mechanism is a double bond with an allylic hydrogen, which in the present case is the terminal vinylidene of polypropylene. Commercial polypropylene resins generally lack this reactive site due to the method of chain termination and even in the new metallocene-based resins where the vinylidene is more prevalent, the high molecular weight of the polymer chain translates into doublebond concentrations too low to accurately identify by modern analytical methods.…”

Section: Introductionmentioning

confidence: 98%

Alder Ene functionalization of polypropylene through reactive extrusion

Thompson

Tzoganakis

Rempel

1999

J. Appl. Polym. Sci.

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A commercial isotactic polypropylene was degraded to increase its terminal vinylidene group concentration, and it was subsequently functionalized with maleic anhydride through the Alder Ene reaction at temperatures above 200°C in a co-rotating twin screw extruder. Characterization of the maleated product by Fourier transform infrared spectroscopy, 1 H NMR, differential scanning calorimetry, and gel permeation chromatography showed the anhydride group to be terminally attached, and the degree of functionalization was determined by infrared analysis. Increased temperature and maleic anhydride concentration, as well as improved mixing in the extruder, were found to improve the extent of the reaction. The catalytic contribution of Lewis acid species was evaluated, and ruthenium chloride was found to increase the extent of the reaction by 16% in comparison with stannous chloride as a catalyst in the Alder Ene reaction.

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The Ene Reaction

Cited by 545 publications

References 143 publications

Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

A parametric study of the terminal maleation of polypropylene through an Alder Ene reaction

Alder Ene functionalization of polypropylene through reactive extrusion

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