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Your search keyword '"Usui, Asuka"' showing total 22 results
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22 results on '"Usui, Asuka"'

18. A Practical Approach for the Oxidation of Unactivated Csp3H Bonds with o-Nitro(diacetoxyiodo)benzene as an Efficient Hypervalent Iodine(III)-Based Oxidizing Agent.

Author

Moteki, Shin A., Selvakumar, Sermadurai, Zhang, Tiexin, Usui, Asuka, and Maruoka, Keiji

Subjects
OXIDATION, CHEMICAL bonds, BENZENE, IODINE, OXIDIZING agents
Abstract

A practical approach for the oxidation of unactivated Csp3H bonds by an ortho-nitrophenyl-substituted hypervalent iodine(III) reagent is presented. The nitro group coordinates to the adjacent iodine center through dipolar interaction, which leads to a single substitution of the acetate ligand by tert-butyl hydroperoxide. As a result, a strong iodanyl radical is formed, which can activate the inert Csp3H bonds in a highly efficient manner. The reagent is stable in the presence of moisture, and can be used for oxidation reactions on semipreparative scale. [ABSTRACT FROM AUTHOR]

Published
2014
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20. ChemInform Abstract: Site-Selective Oxidation of Unactivated C(sp3)-H Bonds with Hypervalent Iodine(III) Reagents.

Author

Moteki, Shin A., Usui, Asuka, Zhang, Tiexin, Alvarado, Cesar R. Solorio, and Maruoka, Keiji

Subjects
*OXIDATION, *CARBON-hydrogen bonds, *CHEMICAL reagents, *CHARTS, diagrams, etc.
Abstract

A diagram is presented which provides data on the site-selective oxidation of unactivated carbon (C) (sp3)-hydrogen (H) bonds with hypervalent iodine (III) reagents.

Published
2014
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21. Metal-free C-H bond activation of branched aldehydes with a hypervalent iodine(III) catalyst under visible-light photolysis: successful trapping with electron-deficient olefins.

Author

Moteki SA, Usui A, Selvakumar S, Zhang T, and Maruoka K

Abstract

Direct acyl radical formation of linear aldehydes (RCH2-CHO) and subsequent hydroacylation with electron-deficient olefins can be effected with various types of metal and nonmetal catalysts/reagents. In marked contrast, however, no successful reports on the use of branched aldehydes have been made thus far because of their strong tendency of generating alkyl radicals through the facile decarbonylation of acyl radicals. Here, use of a hypervalent iodine(III) catalyst under visible light photolysis allows a mild way of generating acyl radicals from various branched aldehydes, thereby giving the corresponding hydroacylated products almost exclusively. Another characteristic feature of this approach is the catalytic use of hypervalent iodine(III) reagent, which is a rare example on the generation of radicals in hypervalent iodine chemistry., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2014
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