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発表論文

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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