Bromination of the 1,2,3,6-tetrahydro-3,6-endo-oxyphthalic anhydride system. Stereochemistry and mechanism of the reaction

Mantecon, Joaquin; Cortés, Luis Eduardo López; Payo-Subiza, Eliseo; Salazar, Arturo

doi:10.1021/jo01287a015

Cited by 6 publications

(1 citation statement)

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“…In the case of 7 the endo-endo configuration requires that the dihedral angles between these protons be close to 90°, resulting in near absence of coupling (20)(21)(22).' In contrast, the endo-exo configuration of 9 requires a dihedral angle of approximately 45", resulting in a significant J,,,, (4.9 Hz).…”

Section: Diadducts 4 and 5 (Table 2 )mentioning

confidence: 99%

Influence of Lewis Acids on the Diels–Alder Reaction. V. The Reaction of Furan with Dimethyl Acetylenedicarboxylate

Mcculloch¹,

Smith²,

McInnes³

1973

Can. J. Chem.

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The Diels-Alder addition of furan to dimethyl acetylenedicarboxylate (DMAD) affords a monoadduct 1. The position and steric course of further addition of furan to the latter are temperature dependent. At temperatures of 50" or below addition occurs mainly at the activated double bond to give et~do-endo 4 and endo-exo 5 diadducts. At 100" addition occurs at the less substituted double bond of the monoadduct to give analogous etrdo-endo 7 and endo-exo 9 diadducts; further addition of furan to the latter at 100' affords four triadducts 12-15. The configurations of all these products were determined by p.m.r. and assignments confirmed by simulation of the spectra.AICI, causes enormous rate enhancement of the Diels-Alder additions of furan to DMAD and to the activated double bond of the monoadduct. In the presence of the Lewis acid the predominant diadduct formed is the endo-exo isomer 5.L'addition du type Diels-Alder du furanne sur I'acCtylenedicarboxylate de dimithyle (DMAD) conduit au produit de monoaddition 1. La positio~l et le mecanisme sterique d'additions supplCmentaires du furanne sur le produit 1 dependent de la temperature. A 50 "C ou en-dessous I'addition se produit principalement sur la double liaison activee pour donner des produits de double addition endo-endo 4 et endo-exo 5. A 100 "C, I'addition se produit sur la double liaison la moins substituie du produit de monoaddition pour donner les produits de double addition analogues et~do-endo 7 et endo-exo 9; des additions supplCmentaires du furanne sur ces derniers produits a 100 "C conduisent a quatre produits de triple addition 12-15. Les configurations de tous ces produits ont CtC dCterminCes par r.m.n. e t les attributions ont CtC confirmkes par simulation des spectres.Le AICI, entraine une augmentation enorme de la vitesse d'addition du type Diels-Alder du furanne sur le DMAD et sur la double liaison activke du oroduit de monoaddition. En oresence de I'acide deLewis. Ie produit majeur de double addition form6 est l'isomkre etldo-e.ro 5.

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Section: Diadducts 4 and 5 (Table 2 )mentioning

confidence: 99%

Influence of Lewis Acids on the Diels–Alder Reaction. V. The Reaction of Furan with Dimethyl Acetylenedicarboxylate

Mcculloch¹,

Smith²,

McInnes³

1973

Can. J. Chem.

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Cycloadditionen von 3,4‐Dimethoxyfuran an Dienophile

Iten

Hofmann

Eugster

1979

Helvetica Chimica Acta

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Herrn Prof. Andre Dreiding zum 60. Geburtstag gewidmet (18.VI. 79) On cycloaddition reactions with 3,4-dimethoxyfuran SummaryWe describe new cycloadditions of 3,4-dimethoxyfuran (3,4-DF, 1) with various dienophiles. In contrast to furan, the reaction of 3,4-DF With maleic anhydride gives exo-and endo-adducts at approximately the same rate. The thermodynamically more stable product is again the exo-product. Less active dienophiles lead also to mixtures of exo-and endo-adducts, exept for citraconic anhydride (methylmaleic anhydride) which forms only the adduct with an endo-methyl group. Dimethylmaleic anhydride could not be reacted with 3,4-DF.All adducts with 3,4-DF contain a hidden 1,2-dicarbonyl group in the form of an endiolether. Its pronounced nucleophilic character allows a series of further additions. Noteworthy are the stereospecific cis-additions of halogens and the preparation of several acetals. Ozonolysis of the enolether in 4 allows the preparation of the hitherto unknown 2r, 3trans, 4truns, Scis-tetrahydrofuran tetracarboxylic acid and derivatives thereof (5 and 6 ) .3,4-Dimethoxyfuran (3,4-DF, 1) ist in Substitutionsreaktionen deutlich reaktiver als Furan selbst'). In dieser Arbeit zeigen wir, dass die gesteigerte Reaktivitat auch bei Cycloadditionen besteht.Die lunetisch kontrollierten Produkte der Cycloaddition von Furan an reaktive Dienophile haben endo-, die thermodynamisch kontrollierten exo-Konfiguration. So bildet sich das endo-Addukt aus Furan und Maleinsaureanhydrid in Acetonitnl 500mal schneller als das exo-Addukt; letzteres ist jedoch 1,9 kcal . mol-I stabiler

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Preparation of 3‐bromo‐2‐methylfuran and 4‐bromo‐2‐methylfuran

Koyanagi

Yamamoto

Nakayama

1994

Journal of Heterocyclic Chem

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4‐endo‐5‐exo‐Dibromo‐3‐methyl‐3,6‐endo‐oxyperhydrophthalic anhydride 3b and 4‐exo‐5‐endo‐dibro‐mo‐3‐methyl‐3,6‐endo‐oxyperhydrophtbalic anhydride 3c were isolated from the bromo‐adducts of 3‐methyl‐3,6‐endo‐oxy‐1,2,3,6‐tetrahydrophthalic anhydride 2. When 3b or 3c was heated in quinoline, only 3‐bromo‐2‐methylfuran 4 was obtained from 3b and only 4‐bromo‐2‐methylfuran 5 from 3c.

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Bromination of the 1,2,3,6-tetrahydro-3,6-endo-oxyphthalic anhydride system. Stereochemistry and mechanism of the reaction

Cited by 6 publications

References 0 publications

Influence of Lewis Acids on the Diels–Alder Reaction. V. The Reaction of Furan with Dimethyl Acetylenedicarboxylate

Influence of Lewis Acids on the Diels–Alder Reaction. V. The Reaction of Furan with Dimethyl Acetylenedicarboxylate

Cycloadditionen von 3,4‐Dimethoxyfuran an Dienophile

Preparation of 3‐bromo‐2‐methylfuran and 4‐bromo‐2‐methylfuran

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