نتایج جستجو برای: diels alder and 1 3 dipolar cycloaddition reactions
تعداد نتایج: 17429646 فیلتر نتایج به سال:
Abstract: 3-(Trifluoromethyl)prop-2-yne 1-iminium triflate salts were generated from 3-trifloxy-3-(trifluoromethyl)prop-2-ene by triethylamine-assisted elimination of triflic acid and trapped in situ various cycloaddition reactions. These included Diels-Alder reactions with 1,3-dienes, [2+2] 1,4-diphenylbuta-1,3-diene, [3+2] organoazides. All these revealed the excellent dienophilic dipolarophi...
Density Functional Theory has been used to model the Diels-Alder reactions of the fullerene fragments triindenetriphenilene and pentacyclopentacorannulene with ethylene and 1,3-butadiene. The purpose is to prove the feasibility of using Diels-Alder cycloaddition reactions to grow fullerene fragments step by step, and to dimerize fullerene fragments, as a way to obtain C₆₀. The dienophile charac...
The first transannular [4 + 2] cycloaddition reactions of macrocyclic dicobalt hexacarbonyl-dienyne complexes were demonstrated. Complexes were conveniently prepared through palladium(II)-catalyzed intramolecular oxidative cyclization of bis(vinylboronate esters) followed by complexation with dicobalt octacarbonyl. Transannular [4 + 2] cycloaddition reactions of the complexes occurred at lower ...
A large number of dienes and dienophiles have been employed in the Diels–Alder reaction to produce cyclohexene products with high facial, regio-, stereo-, and enantioselectivity. The reactions work best when the dienophile is substituted with an electron-withdrawing group. However, often in synthesis, the addition of an ethylene unit to a diene is necessary, and the normal cycloaddition with et...
2,4,6-Triisopropylstryrene was synthesized in a single step via the Witting Reaction from the corresponding aldehyde. The reaction of three styrene's derivatives, 2,6-dimethylstyrene, 2,4,6-trimethylstyrene, and 2,4,6- triisopropylstyrene with 4-methyl-l,2,4-triazoline-3,5-dion(M eTD) was investigated. These reactions are instantaneous at room temperature and lead to the formation of 2: 1 ...
The methyl ether derivatives 2, 4 and 6 of the mulberry Diels-Alder adducts chalcomoracin (1) and mulberrofuran C (3) and kuwanon J (5) respectively have been synthesized by a thermal [4 + 2]-cycloaddition reaction between a chalcone and dehydroprenyl diene. A H-bonded ortho OH substituent on the chalcone was found to be essential for Diels-Alder reactivity. Density functional theory calculatio...
Electron-rich dienes have revolutionized the synthesis of complex compounds since the discovery of the legendary Diels-Alder cycloaddition reaction. This highly efficient bond-forming process has served as a fundamental strategy to assemble many structurally formidable molecules. Amino silyloxy butadienes are arguably the most reactive diene species that are isolable and bottleable. Since the p...
Enynes connected through aromatic rings are used as substrates for metathesis reactions. The reactivity of three ruthenium carbene complexes is compared. The resulting 1,3-dienes are suitable precursors of polycyclic structures via a Diels-Alder process. Some domino RCM-Diels-Alder reactions are performed, suggesting a possible beneficial effect of the ruthenium catalyst in the cycloaddition pr...
The reversibility of the Diels-Alder reaction can be used advantageously in polyurethane materials to endow them with recyclable, thermally reversible properties and self-healing ability to expand their application range. In this paper, linear and crosslink polyurethanes based on HTPB, which exhibit thermal reversibility through Diels-Alder and retro Diels-Alder reactions, were prepared and cha...
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