The Ryu Research Group, Department of Chemistry, Graduate School of Science, Osaka Prefecture University

Osaka Prefecture University School of Science  Department of Chemistry  Access  Sitemap

Publications

Published in 2004

200408
Cascade carbonylation methods leading to β-diketones and β-functionalized δ-diketones
Miura, K., Tojino, M., Fujisawa, N., Hosomi, A., Ryu, I.
Angew. Chem. Int. Ed., 2004, 43, 18 pp. 2423 - 2425
DOI: 10.1002/anie.200453702

A radical combination: An intermolecular cascade reaction involving alkyl halides, CO, electron-deficient alkenes, and stannyl enolates proceeds smoothly by a radical chain pathway to give four-component coupling products in good to high yields (see scheme). A series of 1,5-diketones with a substituent at the 3-position was prepared by this method.

200407
Intramolecular nucleophilic carbonyl trapping of α-ketenyl radicals by an amino group
Tojino, M., Uenoyama, Y., Fukuyama, T., Ryu, I.
Chem. Commun., 2004, , pp. 2482 - 2483
DOI: 10.1039/b408746a

Free-radical carbonylation of ω-alkynylamines with tributyltin hydride gives a mixture of α-methylene lactams and α-stannylmethylene lactams. Nucleophilic addition of an internal amino group to the carbonyl group of α-ketenyl radicals is proposed as the cyclization step. The subsequent unusual 1,4-H shift from the resulting 1-hydroxyallyl radical, followed by elimination of the β-tributyltin radical leads to the formation of α-methylene lactams.

200406
Mizoroki-Heck Arylation of α,β-unsaturated acids with a hybrid fluorous ether, F-626: Facile filtrative separation of products and efficient recycling of a reaction medium containing a catalyst
Fukuyama, T., Arai, M., Matsubara, H., Ryu, I.
J. Org. Chem., 2004, 69, 23 pp. 8105 - 8107
DOI: 10.1021/jo049028+

The Mizoroki−Heck reaction was carried out using a fluorous ether F-626 as the solvent and a fluorous Pd carbene complex as the catalyst. When carboxylic acids are the products, separation of both the F-626 and the Pd catalyst from the products can be conveniently carried out by simple filtration. The F-626 filtrates containing the Pd catalyst can be recycled.

journal_ec
[Bmim]NTf2, a low viscosity ionic liquid is a viable reacttion medium for Pd-catalyzed cross-coupling reactions
Liu, S., Fukuyama, T., Sato, M., Ryu, I.
Synlett., 2004, 10, pp. 1814 - 1816
DOI: 10.1055/s-2004-829552

A low viscosity ionic liquid [bmim]NTf2 was successfully used as a reaction medium in Pd-catalyzed Mizoroki-Heck, Suzuki-Miyaura and Stille coupling reactions. The yields are good to high, and comparable to those reported previously for high viscosity ionic liquids, such as [bmim]PF6 and [bmim]BF4. The products are readily separated and a reaction medium containing the Pd-carbene catalyst was successfully recycled.

journal_ec
Quick execution of [2+2] type photochemical cycloaddition reaction by continuous flow system using a glass-made microreactor
Fukuyama, T., Hino, Y., Kamata, N., Ryu, I.
Chem. Lett., 2004, 33, 11 pp. 1430 -
DOI: 10.1246/cl.2004.1430

A photochemical [2+2] cycloaddition reaction was executed in a microflow system using glass-made microchannels having 1000-μm width and 500-μm depth. The reaction of cyclohexenones with vinyl acetates in a microflow system under irradiation (300 W, Hg lamp) gave [2+2] cycloaddition products in good yield with a residence time of 2 h, which is a remarkably shortened reaction time compared with a batch system using the same light source.

journal_ec
Zinc-induced deoximation of α,β-diketo esters
Ryu, I., Kuriyama, H., Miyazato, H., Minakata, S., Komatsu, M., Yoon, J. -Y., Kim, S.
Bull. Chem. Soc. Jpn., 2004, 77, 7 pp. 1407 - 1408
DOI: 10.1246/bcsj.77.1407

The deoximation of a variety of α,α′-dioxo-type oximes and oxime ethers was achieved under mild conditions using zinc/AcOH, which gave good yields of α,β-diketo esters.

journal_ec
Continuous microflow synthesis of butyl cinnamate by a Mizoroki-Heck reaction using a low viscosity ionic liquid as the recycling reaction medium
Liu, S., Fukuyama, T., Sato, M., Ryu, I.
Org. Process Res., 2004, 8, 3 pp. 477 - 481
DOI: 10.1021/op034200h

A continuous microflow system was developed with efficient catalyst recycling for a Mizoroki−Heck reaction of iodobenzene with butyl acrylate, using a low-viscosity ionic liquid ([bmim]NTf2) as the reaction medium. Using a CPC CYTOS Lab System as the microreaction apparatus, in combination with an originally developed microextraction/catalyst recycling system, the reaction medium, which contained Pd catalyst could be continuously recycled to provide a total of 115.3 g (80%, 10 g/h) of the desired product.

journal_ec
Radical carbonylation of 1,5-enynes using TTMSS as a chain carrier. Unexpected formation of persistent 3-silyl-1-siloxyallyl serving as a chain breaking path
Fukuyama, T., Uenoyama, Y., Oguri, S., Otsuka, N., Ryu, I.
Chemistry Letters., 2004, 33, 7 pp. 854 - 855
DOI: 10.1246/cl.2004.854

The radical carbonylation of 1,5-enynes 1a and 1b using TTMSS as radical mediator gave the predicted carbonylative cyclization products 2a and 2b, respectively, in poor yields. The isolation and characterization of reaction byproducts by X-ray crystallographic analysis suggest that the poor chain propagation can be attributed to the formation of long-lived 3-silyl-1-siloxyallyl radicals, produced by the addition of a (TMS)3Si radical onto the O–C double bond of the initially formed cyclopentanones.

 

 

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Laboratory for Advanced Organic Synthesis
Organization for Research Promotion Osaka Prefecture University
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