Hypervalent iodine(III): selective and efficient single-electron-transfer (SET) oxidizing agent
作者:Toshifumi Dohi、Motoki Ito、Nobutaka Yamaoka、Koji Morimoto、Hiromichi Fujioka、Yasuyuki Kita
DOI:10.1016/j.tet.2009.10.040
日期:2009.12
ethers, affording the corresponding aromatic cation radicals. Since then, hypervalent iodine(III) has been utilized as a selective and efficient SET oxidizingagent that enables a variety of direct C–H functionalizations of aromatic rings in electron-rich arenes under mild conditions. We have now extended the original method to work in a series of heteroaromatic compounds such as thiophenes, pyrroles,
Novel and Direct Oxidative Cyanation Reactions of Heteroaromatic Compounds Mediated by A Hypervalent Iodine(III) Reagent
作者:Toshifumi Dohi、Koji Morimoto、Yorito Kiyono、Hirofumi Tohma、Yasuyuki Kita
DOI:10.1021/ol0476826
日期:2005.2.1
The hypervalent iodine(III) reagent phenyliodine bis(trifluoroacetate) (PIFA) mediates the selective cyanation reactions of a wide range of electron-rich heteroaromatic compounds such as pyrroles, thiophenes, and indoles under mild conditions. These reactions proceed via a cation radical intermediate, and the key for the successful transformation presumably depends on the oxidation-reduction potential
Direct Synthesis of Bipyrroles Using Phenyliodine Bis(trifluoroacetate) with Bromotrimethylsilane
作者:Toshifumi Dohi、Koji Morimoto、Akinobu Maruyama、Yasuyuki Kita
DOI:10.1021/ol060333m
日期:2006.5.1
[reaction: see text] The hypervalent iodine(III) reagent, phenyliodinebis(trifluoroacetate) (PIFA), mediates the unprecedented, oxidative coupling reaction of pyrroles to give alpha-linked bipyrroles selectively in the presence of bromotrimethylsilane. This straightforward synthesis could provide 2,3'-bipyrrole by the choice of a N-substituent of pyrrole. Mechanistic consideration of the present reaction
Regioselective Bipyrrole Coupling of Pyrroles and 3-Substituted Pyrroles Using Phenyliodine(III) Bis(trifluoroacetate)
作者:Yasuyuki Kita、Toshifumi Dohi、Koji Morimoto、Motoki Ito
DOI:10.1055/s-2007-983798
日期:2007.9
A series of electron-rich bipyrroles were prepared by the regioselective, phenyliodine(III) bis(trifluoroacetate) (PIFA) induced oxidative coupling of pyrroles in the presence of bromotrimethylsilane. Using pyrrole and 3,4-disubstituted pyrroles gave exclusively 2,2′-linked bipyrroles without the formation of other bipyrrole regioisomers. The 3-alkyl- or 3-aryl-substituted pyrroles gave unsymmetrical
to the corresponding C-silylation in the case that the nitrogen atom of indoles has a substituent. Pyrrole, carbazole, arylamine, and thiophene substrates other than indoles undergo the dehydrogenative N- and/or C-silylation as well. Mechanistic studies showed that the role of the zinc Lewis acid is to activate the hydrosilane. The rate-determining step of the present reaction was found to be involved