Synthetic Connections to the aromatic directed metalation reaction. Radical-induced cyclization to substituted benzofurans, benzopyrans, and furopyridines

Shankaran, K.; Sloan, Charles P.; Snieckus, Victor

doi:10.1016/s0040-4039(00)95109-8

Cited by 84 publications

(18 citation statements)

References 14 publications

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“…The aqueous layer was extracted with ether. The ethereal extracts were dried, concentrated, and purified by flash chromatography (10% ethyl acetate in hexane) to give the xanthate ester (2b), (30% yield);ir: 1720, 1660, 1225, and 1065 cm-'; 'Hnmr (400MHz) 6:6.945 (dt,lH,J = 15.6Hz,6. …”

Section: Erhyl7-s-methyl Dithiocarbonoloxy-2-(e)-heptenoate 2 Bmentioning

confidence: 99%

“…The utilization of radical reactions for carbon-carbon bond formation in synthetic organic chemistry has recently attracted considerable interest (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). The increasing popularity of radical-based synthetic methods in organic synthesis is attribu- Preparation of intermediates The radical vrecursors 2 for the intramolecular cvclization were prepared from the corresponding lactones2* using a three-step reaction sequence outlined in Scheme 1.…”

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confidence: 99%

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Synthesis of carbocycles from ω-substituted α,β-unsaturated esters via radical-induced cyclizations

Hanessian¹,

Dhanoa²,

Beaulieu³

1987

Can. J. Chem.

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The intramolecular radical cyclization of o-bromo a,P-unsaturated esters for the synthesis of carbocyclic compounds is described. The effect of carbon chain substituents, the bulk of the ester group, and the olefin geometry were examined. The highest level of stereoselectivity (translcis: 911) was achieved with the Z ester via an exo cyclization. The sequential radical cyclization of a dihalodienoate to give a cis-fused bicyclic structure is also described. STEPHEN HANESSIAN, DALJIT S. DHANOA et PIERRE L. BEAULIEU. Can. J . Chem. 65, 1859 (1987.Nous dCcrivons l'utilisation d'une reaction de cyclisation radicalaire intramolCculaire des esters w-bromo a,p-insatures pour la synthkse de composCs carbocycliques. Nous avons CtudiC les paramktres suivants : la substitution de la chaine, I'encombrement stCrique dfi 21 l'ester ainsi que la gComCtrie de la double liaison des prCcurseurs radicalaires. Le plus haut degrC de stCreosClection (translcis: 911) fut obtenu avec l'ester a,p-insaturC Z. exo. De plus, la cyclisation radicalaire en sCrie d'un dihalogkno dienoate donne un produit bicyclique.The utilization of radical reactions for carbon-carbon bond formation in synthetic organic chemistry has recently attracted considerable interest (1-10). The increasing popularity of radical-based synthetic methods in organic synthesis is attribu-

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Section: Erhyl7-s-methyl Dithiocarbonoloxy-2-(e)-heptenoate 2 Bmentioning

confidence: 99%

mentioning

confidence: 99%

Synthesis of carbocycles from ω-substituted α,β-unsaturated esters via radical-induced cyclizations

Hanessian¹,

Dhanoa²,

Beaulieu³

1987

Can. J. Chem.

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“…Note that all these yields can most likely be improved by fine‐tuning the excess of bipy (compare Table 2, entries 10 and 11). The 6‐ exo‐dig and, particularly, 7 ‐exo‐dig character of the cyclizations of 1 f and 1 g (Table 2, entries 5 and 6, respectively) are worth underlining because, to our knowledge, there are only a limited number of comparable examples in literature, and they principally use palladium catalysis37 or radical cyclization 33a–d. 38…”

Section: Resultsmentioning

confidence: 99%

Gas‐phase ethylene polymerization over polymer‐supported metallocene catalysts

Zhou

et al. 2003

J of Applied Polymer Sci

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ABSTRACT:The activities of two (n-BuCp) 2 ZrCl 2 catalysts supported on methylaluminoxane (MAO)-treated polymer particles were evaluated. The supports were spherical polymeric particles, containing macropores and prepared by suspension polymerization of 2-hydroxyethyl methacrylate, divinyl benzene, ethyl styrene, and styrene. Both catalysts had a Zr content of 0.31 mass % and an Al/Zr ratio of 185; the supports for one of the catalysts contained 59 mass % 2-hydroxyethyl methacrylate, whereas the support for the other catalyst had a 2-hydroxyethyl methacrylate content of 10 mass %. Ethylene homo-and ethylene/1-hexene copolymerization activities were determined for gas-phase operation at temperatures of 50 to 90°C and ethylene pressures of Ϸ1.4 MPa. Polymerization activities were strong functions of temperature and 1-hexene concentration; copolymerization activities of up to 23,200 kg PE/(mol Zr h Ϫ1 ) were obtained for 1-h polymerization runs. The product particle morphology was excellent, mostly spherical particles essentially without fines. Scanning electron microscopy showed that the spherical copolymer particles, for all copolymerization conditions, consisted of well-defined concentric spherical shells.

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“…Some cinnamates are inhibitors of plant growth and in the future could play an important role as agrochemicals against some important pests. Particularly, aryl cinnamates have been used as intermediates for diverse heterocyclic compounds, such as flavanones, chromones, pirazols, dihydrocoumarins, and benzofuranones . Additionally, coumarins and their derivatives are widely applied.…”

Section: Introductionmentioning

confidence: 99%

“…Particularly, aryl cinnamates have been used as intermediates for diverse heterocyclic compounds, such as flavanones, [5] chromones, [6] pirazols, [7] dihydrocoumarins, [7,8] and benzofuranones. [9] Additionally, coumarins and their derivatives are widely applied. They are mainly used as active components in the formulation of pesticides and additives in the manufacture of pharmaceuticals, food, and cosmetics.…”

Section: Introductionmentioning

confidence: 99%

Molecular structure, experimental and theoretical¹H and¹³C NMR chemical shift assignment of cyclic and acyclic α,β-unsaturated esters

Buceta

Ruiz

Romanelli

et al. 2013

J. Phys. Org. Chem.

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The experimental 1H and 13C NMR spectra of 13 phenyl cinnamates and four 4‐methylcoumarins were investigated and their chemical shifts assigned on the basis of the two‐dimensional spectra. For the unsubstituted cinnamic acid phenyl ester, optimized molecular structures were calculated at a B3LYP/6‐311++G(d,p) level of theory. 1H and 13C NMR chemical shifts were also calculated with the GIAO method at the B3LYP/6‐311 + G(2d,p) level of theory. The comparison between experimental and calculated NMR chemical shift suggests that the experimental spectra are formed from the superposition spectra of the two lowest energy conformers of the compound in solution. The most stable s‐cis configuration found in our studies is also the conformation adopted for a related phenyl cinnamate in solid state. The experimental results were analyzed in terms of the substituent effects. Copyright © 2013 John Wiley & Sons, Ltd.

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Synthetic Connections to the aromatic directed metalation reaction. Radical-induced cyclization to substituted benzofurans, benzopyrans, and furopyridines

Cited by 84 publications

References 14 publications

Synthesis of carbocycles from ω-substituted α,β-unsaturated esters via radical-induced cyclizations

Synthesis of carbocycles from ω-substituted α,β-unsaturated esters via radical-induced cyclizations

Gas‐phase ethylene polymerization over polymer‐supported metallocene catalysts

Molecular structure, experimental and theoretical¹H and¹³C NMR chemical shift assignment of cyclic and acyclic α,β-unsaturated esters

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Synthetic Connections to the aromatic directed metalation reaction. Radical-induced cyclization to substituted benzofurans, benzopyrans, and furopyridines

Cited by 84 publications

References 14 publications

Synthesis of carbocycles from ω-substituted α,β-unsaturated esters via radical-induced cyclizations

Synthesis of carbocycles from ω-substituted α,β-unsaturated esters via radical-induced cyclizations

Gas‐phase ethylene polymerization over polymer‐supported metallocene catalysts

Molecular structure, experimental and theoretical1H and13C NMR chemical shift assignment of cyclic and acyclic α,β-unsaturated esters

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Product

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Molecular structure, experimental and theoretical¹H and¹³C NMR chemical shift assignment of cyclic and acyclic α,β-unsaturated esters