The University of Tokyo · Materials Science
Professor Kazunori Miyamoto's research lab specializes in the development of novel hypervalent iodine(III)- and iodine(V)-based reagents for selective and efficient organic transformations. The lab focuses on metal-free oxidative cleavage of C–C multiple bonds, catalytic Hofmann rearrangements, and the generation of reactive intermediates such as diatomic carbon (C₂) under mild conditions. A central theme is the design of innovative organocatalytic and hypervalent iodine-catalyzed reactions that replace traditional toxic or harsh oxidants with safer, more sustainable alternatives.
Figures are computed from collected data and may differ slightly.
Transition metal-catalyzed oxidative cleavage of carbon-carbon multiple bonds has emerged as a powerful tool in organic synthesis. High-valent oxometals, mostly of Ru, Os, Mn, Mo, W, and Re, were used catalytically as reactive oxygen transfer agents to the multiple bonds. Reported here for the first time are the organocatalytic versions of the oxidative cleavage reactions. Our method involves use of iodomesitylene as an effective organocatalyst, which generates an active aryl(hydroxy)-lambda(3)-
Reported here for the first time are the developments of an efficient method for oxidative cleavage of carbon−carbon double bonds yielding carbonyl compounds by using aryl-λ3-iodanes, which involve a combination of iodosylbenzene and HBF4 in the presence of water. The method serves as a safety alternative to ozonolysis. The oxidative cleavage of olefins probably involves the hitherto unknown direct vicinal dihydroxylations of double bonds with aryl-λ3-iodanes and the subsequent oxidative glycol
Molecular oxygen serves as a useful oxidant for the glycol scission of 1,2-diols and the Hofmann rearrangement of primary amides using pentamethyliodobenzene as a catalyst. The use of isobutyraldehyde and Lewis basic nitriles under O<sub>2</sub> enabled the iodine(i)/(iii) catalytic cycle, where in situ-generated peracid acts as a terminal oxidant.
The first catalytic version of hypervalent aryl-λ(3)-iodane-induced Hofmann rearrangement of primary carboxamides, which probably involves in situ generation of a tetracoordinated bis(aqua)(hydroxy)phenyl-λ(3)-iodane complex as an active oxidant from a catalytic amount of iodobenzene by the reaction with m-chloroperbenzoic acid in the presence of HBF(4) in dichloromethane-water under mild conditions, was developed.
Diatomic carbon (C<sub>2</sub>) is historically an elusive chemical species. It has long been believed that the generation of C<sub>2</sub> requires extremely high physical energy, such as an electric carbon arc or multiple photon excitation, and so it has been the general consensus that the inherent nature of C<sub>2</sub> in the ground state is experimentally inaccessible. Here, we present the chemical synthesis of C<sub>2</sub> from a hypervalent alkynyl-λ<sup>3</sup>-iodane in a flask at roo
The isolation and intramolecular cyclization of (S)-(1-alkynyl)isothiouronium and (S)-(1-alkynyl)thiobenzimidonium salts suggest the mechanism for the one-pot synthesis of 2,4-disubstituted thiazoles (see scheme; Ms=methanesulfonyl): Michael addition of sulfur nucleophiles to hypervalent iodanes followed by the 1,2-rearrangement of sulfenyl groups in the resulting alkylidene carbenes.
We have developed a versatile, high-yield synthesis of diarylchloroniums/λ<sup>3</sup>-chloranes through the reaction of various chloroarenes with readily prepared mesityldiazonium tetrakis(pentafluorophenyl)borate under mild conditions. The scope of the reaction is broad, including ArCl, ArBr, and ArI. The diarylchloroniums/λ<sup>3</sup>-chloranes prepared here show unique reactivity in various respects, enabling intermolecular electrophilic arylation reaction of weak nucleophiles, and chlorane
Exposure of 3-phenylpropyl ethers to an activated iodosylbenzene monomer·18-crown-6 complex [PhI(OH)BF(4)·18C6] in the presence of BF(3)-Et(2)O and water results in the para-selective monofluorination of benzene ring via neighboring alkoxy group participation and directly affords 3-(4-fluorophenyl)propyl ethers regioselectively in good yields.
A practical method for the preparation of (diacetoxyiodo)arene ArI(OAc)<sub>2</sub> is described. The use of commercially available sodium hypochlorite pentahydrate (NaClO·5H<sub>2</sub>O) enabled safe, rapid, and inexpensive oxidation of iodoarenes with electron-withdrawing and -donating substituents. The method allows tandem divergent access to synthetically useful organo-λ<sup>3</sup>-iodanes such as hydroxyl(tosyloxy)iodobenzene, iodosylbenzene, iodonium ylide, etc.
We present the first synthesis of air/moisture-stable λ<sup>3</sup>-bromanes (<b>9</b> and <b>10</b>) by using a cyclic 1,2-benzbromoxol-3-one (BBX) strategy. X-ray crystallography and NMR and IR spectroscopy of <i>N</i>-triflylimino-λ<sup>3</sup>-bromane (<b>12</b>) revealed that the bromine(III) center is effectively stabilized by intramolecular R-Br-O hypervalent bonding. This strategy enables the synthesis of a variety of air-, moisture-, and benchtop-stable Br-hydroxy, -acetoxy, -alkynyl, -
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