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


Published in 2002

Phase-vanishing reactions that use fluorous media as a phase screen. Facile, controlled bromination of alkenes by dibromine and dealkylation of aromatic ethers by bron tribromide
Ryu, I., Matsubara, H., Yasuda, S., Nakamura, H., Curran, D. P.
J. Am. Chem. Soc., 2002, 124, 44 pp. 12946 - 12947
DOI: 10.1021/ja027965y

In fluorous triphasic reactions, such as bromination of alkenes by dibromine and dealkylation of aromatic ethers by boron tribromide, the middle fluorous phase acts as a liquid membrane permitting passive transport of the reagents at the bottom to the top layer involving the substrates, thereby regulating the reactions.

Cascade radical reactions catalyzed by a Pd/Light system: Cyclizative multiple carbonylation of 4-alkenyl iodines
Ryu, I., Kreimerman, S., Araki, F., Nishitani, S., Oderaotoshi, Y., Minakata, S., Komatsu, M.
J. Am. Chem. Soc., 2002, 124, 15 pp. 3812 - 3813
DOI: 10.1021/ja017315e

Cascade reactions of 4-alkenyl iodides, involving a carbonylation−cyclization−carbonylation sequence, were accomplished by a hν/Pd system. The stereochemical outcomes suggest that radical carbonylation and subsequent acyl radical cyclization may be involved in this reaction.

5-Azahexenoyl radicals cyclize via nucleophilic addition to the acyl carbon rather than 5-exo homolytic addition at the imine
Falzon, C., Ryu, I., Schiesser, C.
Chem. Commun., 2002, , pp. 2338 - 2339
DOI: 10.1039/b207729a

Molecular orbital calculations predict that the 5-azahexenoyl radical ring closes via nucleophilic addition to the acyl carbon to afford the 5-exo product; CCSD(T)/cc-pVDZ//BHLYP/cc-pVDZ calculations predict energy barriers of 36.1 and 46.9 kJ mol–1 for the exo and endo cyclization modes of the 5-azahexenoyl radical, respectively.

A copper-free Sonogashira coupling reaction in ionic liquids and its application to a microflow system for efficient catalyst recycling
Fukuyama, T., Shinmen, M., Nishitani, S., Sato, M., Ryu, I.
Org. Lett., 2002, 4, 10 pp. 1691 - 1694
DOI: 10.1021/ol0257732

The PdCl2(PPh3)2-catalyzed Sonogashira coupling reaction, in good to high yields, was performed in an ionic liquid ([BMIm][PF6]) in the absence of a copper salt. The use of an ionic liquid allows for the facile separation and recycling of the catalyst. The application of the above reaction in a microflow system in conjunction with an IMM micromixer was also successful.

A new fluorous/organic amphiphilic ether solvent, F-626: execution of fluorous and high temperature classical reactions with convenient biphase workup to separate product from high boiling solvent
Matsubara, H., Yasuda, S., Sugiyama, H., Ryu, I., Fujii, Y. , Kita, K.
Tetrahedron, 2002, 58, 20 pp. 4071 - 4076
DOI: 10.1016/S0040-4020(02)00256-9

A new fluorous/organic amphiphilic ether solvent, 1H,1H,2H,2H-perfluorooctyl 1,3-dimethylbutyl ether (F-626), is introduced. The basic properties of F-626, especially the partition coefficients with organic solvents/FC-72 (perfluorohexane), were investigated. F-626 was easy to remove by fluorous biphase treatment. Using F-626 as a solvent, LAH reduction, catalytic hydrogenation, and fluorous reductive radical reactions were successful. Classical high temperature reactions up to 200°C, such as the Vilsmeier formylation, the Wolff–Kishner reduction, and the Diels–Alder reaction, were also examined in F-626. The yields of the products in F-626 were almost comparable with those conducted in common organic solvents, which prove that F-626 has the potential to be an easily recyclable high boiling solvent.

Chemistry of ketone α,β-dianions. Acylation reactions of dianion cuprates by acid chlorides
Ryu, I., Ikebe, M., Sonoda, N., Yamato, S., Yamamura, G., Komatsu, M.
Tetrahedron Lett., 2002, 43, 7 pp. 1257 - 1259
DOI: 10.1016/S0040-4039(01)02346-2

The cross-coupling reaction of dianion cuprates, generated from ketone α,β-dianions and copper salts, with acid chlorides, was studied. The reaction gave good to moderate yields of unsymmetrical 1,4-diketones. The consecutive treatment of a dianion cuprate with cyclohexanecarbonyl chloride and methyl iodide or two different acid chlorides gave 2-methyl-substituted 1,4-diketone or triketone, respectively.



Laboratory for Advanced Organic Synthesis
Organization for Research Promotion Osaka Prefecture University
Sakai, Osaka 599-8531, JAPAN
Mail:ryu --at-- Replace @ instead of  "--at--".