Dimenthyl Fumarate Research Articles

ChemInform Abstract: Thermal and Lewis Acid Promoted Novel Asymmetric Hetero Diels-Alder Reactions of a 1-Thiabuta-1,3-diene System (Thiochalcones) with (-)- Dimenthyl Fumarate.

Thermal and Lewis acid-promoted reactions of thiochalcones with (–)-dimenthyl fumarate gave two 3,4-cis-cycloadducts, 4 and 5, in good yields with 100%endo-diastereoselectivity and with a high level of diastereofacial selectivity. The major product 4 could be obtained stereochemically pure by recrystallization and this, when reduced with LiAlH4, gave the optically active diol 6. The latter was converted into the acyclic diol 8 by Raney-Ni desulphurization.

ChemInform Abstract: The Effect of Alumina on the Diels-Alder Reactions of Cyclopentadiene with Menthyl Acrylate and Dimenthyl Fumarate.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Asymmetric Diels—Alder Reaction of 1,3‐Butadienes with (—)‐Dimenthyl Fumarate in the Presence of BBr3 and BBr3×OEt2.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Asymmetric Diels-Alder reaction of 1,3-butadienes with (−)-dimenthyl fumarate in the presence of BBr3 and BBr3·OEt2

Asymmetric synthesis of substituted cyclohexenes was performed by [4+2]-cycloaddition of (-)-dimenthyl fumarate to 1,3-butadienes in the presence of BBr3 and BBr3·OEt2. The latter are efficient catalysts for this reaction. The effect of various factors on the chemical and optical yield of compounds synthesized was studied. The lowering of the reaction temperature to −70°C favors increase in the enantiomeric purity of products up to 81%. The overall yield of adducts grows with temperature and catalyst amount. The solvent character insignificantly affects the overall and optical yield of compounds obtained.

Lewis-acid catalysis of the asymmetric Diels–Alder reaction of dimenthyl fumarate and cyclopentadiene

The effects of Lewis acid catalysts, solvent, catalyst loading, and temperature on the diastereomeric excess in the Diels–Alder reaction of (+)-dimenthyl fumarate and cyclopentadiene were investigated.

Design and Synthesis of Foldamers Based on an Anthracene Diels–Alder Adduct

A twelve-membered hydrogen-bonded ring and the resulting helical structure (see picture) in the tetrapeptide and an eight-membered hydrogen-bonded ring in the dipeptide illustrate the structural consequences of the incorporation of the novel β-amino acid derived from the Diels–Alder adduct of anthracene and dimenthyl fumarate.

Design and Synthesis of Foldamers Based on an Anthracene Diels-Alder Adduct

A twelve-membered hydrogen-bonded ring and the resulting helical structure (see picture) in the tetrapeptide and an eight-membered hydrogen-bonded ring in the dipeptide illustrate the structural consequences of the incorporation of the novel β-amino acid derived from the Diels–Alder adduct of anthracene and dimenthyl fumarate.

A Practical Asymmetric Synthesis of the Antiviral Agent Lobucavir, BMS-180194

A practical synthesis of the antiviral agent lobucavir, [1R-(1α,2β,3α)]-2-amino-9-[2,3-bis(hydroxymethyl)cyclobutyl]-6H-purin-6-one (BMS-180194), is described. The key chiral intermediate, [1S-(1α,2β,3α)]-3-hydroxy-1,2-cyclobutanedimethanol, dibenzoate ester, was made by an asymmetric [2 + 2] cycloaddition of dimenthyl fumarate with ketene dimethyl acetal followed by sequential diester reduction, benzoylation, deketalization, and stereoselective ketone reduction. Regioselective N9-alkylation of the tetra-n-butylammonium salt of 2-amino-6-iodopurine with the derived cyclobutyltriflate furnished the purinecyclobutyl dibenzoate. Methanolysis followed by acid hydrolysis produced lobucavir in a 35% overall yield with an ee > 99%.

Enantioselective Total Synthesis of (+)-Isoboonein.

Enantioselective total synthesis of (+)-isoboonein, an iridoid lactone, was accomplished from (-)-dimenthyl bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate, which was synthesized by diastereoselective Diels-Alder reaction of dimenthyl fumarate with cyclopentadiene.

ChemInform Abstract: Diastereoselectivities in the Diels‐Alder Reactions of Cyclopentadiene with Optically Active Dimenthyl Fumarate and Menthyl Methyl Fumarate in LiClO4/Ether and on Al2O3

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Diastereoselectivities in the diels-alder reactions of cyclopentadiene with optically active dimenthyl fumarate and menthyl methyl fumarate in LiClO 4/ether and on Al 2O 3

Reactions of cyclopentadiene with (−)-dimenthyl fumarate, which yield adducts 1 and 2, and with (−)-menthyl methyl fumarate, which yield adducts 3 through 6, were carried out on alumina activated at different temperatures, in LiClO 4/ether solutions, and in other media. Various diastereoselectivities - 2:1,3:4, 6:5, endo:exo [( 3+ 4): ( 5+ 6)], and % de [( 3+ 6) - ( 4+ 5)]/[ 3+ 4+ 5+ 6] × 100] - were determined for these reactions. The LiClO 4 data were analyzed using a model in which LiClO 4 reversibly binds to the dienophile, resulting in competing catalyzed and uncatalyzed Diels-Alder reactions. Even in approximately 5 M LiClO 4, there are sizable contributions from uncatalyzed reactions in all cases. Extrapolation of the data to infinite LiClO 4 concentration yields data for the catalyzed reactions alone; only modest diastereoselectivities are seen for the catalyzed reactions. The alumina results were unusual because the endo:exo ratios of adducts were large but % de's were small. The selectivities on alumina could not be correlated to the activity of the solid. This behavior will occur when varying numbers and types of catalytic sites are exposed to the surface on activation.

A chemical, spectroscopic, and theoretical assessment of the Lewis acidity of lithium perchlorate in diethyl ether

Moderate diastereoselectivity is observed in the reaction of cyclopentadiene with dimethyl maleate and optically active dimenthyl fumarate in LiClO 4 /diethyl ether. Moderate regioselectivity is also seen in the reaction of isoprene and methyl acrylate in the same medium. NMR experiments and MNDO calculations, in conjunction with published work on Li + in the gas phase, demonstrate that the strong, intrinsic Lewis acidity of Li + is moderated in ether by complexation to the solvent and the counterion

The effect of alumina on the Diels-Alder reactions of cyclopentadiene with menthyl acrylate and dimenthyl fumarate.

Alumina catalyzes the Diels-Alder reactions of cyclopentadiene with optically active menthyl acrylate and dimenthyl fumarate. Significant diastereoselectivity is observed in each case.

Thermal and Lewis acid-promoted novel asymmetric hetero Diels–Alder reactions of a 1-thiabuta-1,3-diene system (thiochalcones) with (–)-dimenthyl fumarate

Thermal and Lewis acid-promoted reactions of thiochalcones with (–)-dimenthyl fumarate gave two 3,4-cis-cycloadducts, 4 and 5, in good yields with 100%endo-diastereoselectivity and with a high level of diastereofacial selectivity. The major product 4 could be obtained stereochemically pure by recrystallization and this, when reduced with LiAlH4, gave the optically active diol 6. The latter was converted into the acyclic diol 8 by Raney-Ni desulphurization.

ChemInform Abstract: Asymmetric Diels‐Alder Reaction. Cooperative Blocking Effect in Organic Synthesis.

Abstract Remarkably high diastereoselectivity is observed in the organoaluminum catalyzed asymmetric Diels-Alder reaction of (-)-dimenthyl fumarate.

Asymmetric diels-alder reaction. Cooperative blocking effect in organic synthesis

Remarkably high diastereoselectivity is observed in the organoaluminum catalyzed asymmetric Diels-Alder reaction of (-)-dimenthyl fumarate.

Partial asymmetric synthesis in the diels-alder reaction

The Diels-Alder condensation of (−)-dimenthyl fumarate with butadiene followed by reduction of the adduct with LiAlH 4, produced (−)-(1R:2R)-4-cyclohexene- trans-1,2-dimethanol in 1–3% optical purity depending on the temperature used to carry out the reaction. However, when AlCl 3, SnCl 4 or TiCl 4 are used to catalyze the reaction then the condensation occurs at much lower temperatures and the product after reduction with LiA1H 4 has the opposite sign and configuration. Furthermore the optical purity of the product ranges from 27–78% depending on reaction conditions. Parameters such as solvent, temperature and catalyst, as they affect asymmetric syntheses, are discussed.