Papers - Miyamoto, Kazunori

One-step Conversion of Levulinic Acid to Succinic Acid Using I2/t-BuOK System: The Iodoform Reaction Revisited

Ryosuke Kawasumi, Shodai Narita, Kazunori Miyamoto, Ken-ichi Tominaga, Ryo Takita, Masanobu Uchiyama

Scientific Reports 7 ( 1 )  2017.12

Accepted

　View Summary

The iodoform reaction has long been used as a qualitative test for acetyl and/or ethanol units in organic molecules. However, its synthetic applications are quite limited. Here, we describe a tuned iodoform reaction for oxidative demethylation reaction with I2 and t-BuOK in t-BuOH, in which in situ-generated t-BuOI serves as the chemoselective iodinating agent. This system enables one-step conversion of levulinic acid to succinic acid, a major four-carbon chemical feedstock. This oxidative demethylation is also applicable to other compounds containing an acetyl group/ethanol unit, affording the corresponding carboxylic acids in a selective manner.

• Access to Document (DOI)

Transition Metal-Free trans-Selective Alkynylboration of Alkynes

Marina Nogami, Keiichi Hirano, Misae Kanai, Chao Wang, Tatsuo Saito, Kazunori Miyamoto, Atsuya Muranaka, Masanobu Uchiyama

Journal of the American Chemical Society (American Chemical Society ({ACS}))  139 ( 36 ) 12358 - 12361 2017.09

ISSN  00027863

　View Summary

We report the first transition metal-free and trans-selective alkynylboration reaction of alkynes. This unprecedented carboboration reaction is enabled by pseudo-intramolecular activation of alkynylboronates using propargylic alcohols. The carboboration affords 4-alkynyl-1,2-oxaborol-2(5H)-ols, which are not only versatile building blocks but also exhibit strong violet-blue fluorescence emission.

• Access to Document (DOI)

Iodoarene-catalyzed oxidative transformations using molecular oxygen

K. Miyamoto, J. Yamashita, S. Narita, Y. Sakai, K. Hirano, T. Saito, C. Wang, M. Ochiai, M. Uchiyama

Chemical Communications (Royal Society of Chemistry ({RSC}))  53 ( 70 ) 9781 - 9784 2017

ISSN  13597345

　View Summary

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 O2 enabled the iodine(i)/(iii) catalytic cycle, where in situ-generated peracid acts as a terminal oxidant.

• Access to Document (DOI)

Cross-Coupling of Organolithium with Ethers or Aryl Ammonium Salts by C-O or C-N Bond Cleavage

Ze-Kun Yang, Dong-Yu Wang, Hiroki Minami, Hiroyuki Ogawa, Takashi Ozaki, Tatsuo Saito, Kazunori Miyamoto, Chao Wang, Masanobu Uchiyama

CHEMISTRY-A EUROPEAN JOURNAL (WILEY-V C H VERLAG GMBH)  22 ( 44 ) 15693 - 15699 2016.10

Accepted,  ISSN  09476539

　View Summary

Various aryl-, alkenyl-, and/or alkyllithium species reacted smoothly with aryl and/or benzyl ethers with cleavage of the inert C-O bond to afford cross-coupled products, catalyzed by commercially available [Ni(cod)(2)] (cod=1,5-cyclooctadiene) catalysts with N-heterocyclic carbene (NHC) ligands. Furthermore, the coupling reaction between the aryllithium compounds and aryl ammonium salts proceeded under mild conditions with C-N bond cleavage in the presence of a [Pd(PPh3)(2)Cl-2] catalyst. These methods enable selective sequential functionalizations of arenes having both C-N and C-O bonds in one pot.

• Access to Document (DOI)

Stille coupling via C-N bond cleavage

Dong-Yu Wang, Masatoshi Kawahata, Ze-Kun Yang, Kazunori Miyamoto, Shinsuke Komagawa, Kentaro Yamaguchi, Chao Wang, Masanobu Uchiyama

NATURE COMMUNICATIONS (NATURE PUBLISHING GROUP)  7   12937 2016.09

Accepted,  ISSN  2041-1723

　View Summary

Cross-coupling is a fundamental reaction in the synthesis of functional molecules, and has been widely applied, for example, to phenols, anilines, alcohols, amines and their derivatives. Here we report the Ni-catalysed Stille cross-coupling reaction of quaternary ammonium salts via C-N bond cleavage. Aryl/alkyl-trimethylammonium salts [Ar/R-NMe3](+) react smoothly with arylstannanes in 1: 1 molar ratio in the presence of a catalytic amount of commercially available Ni(cod)(2) and imidazole ligand together with 3.0 equivalents of CsF, affording the corresponding biaryl with broad functional group compatibility. The reaction pathway, including C-N bond cleavage step, is proposed based on the experimental and computational findings, as well as isolation and single-crystal X-ray diffraction analysis of Ni-containing intermediates. This reaction should be widely applicable for transformation of amines/quaternary ammonium salts into multi-aromatics.

• Access to Document (DOI)

Direct Hydroxylation and Amination of Arenes via Deprotonative Cupration

Noriyuki Tezuka, Kohei Shimojo, Keiichi Hirano, Shinsuke Komagawa, Kengo Yoshida, Chao Wang, Kazunori Miyamoto, Tatsuo Saito, Ryo Takita, Masanobu Uchiyama

Journal of the American Chemical Society (American Chemical Society)  138 ( 29 ) 9166 - 9171 2016.07

ISSN  00027863

　View Summary

Deprotonative directed ortho cupration of aromatic/heteroaromatic C-H bond and subsequent oxidation with t-BuOOH furnished functionalized phenols in high yields with high regio- and chemoselectivity. DFT calculations revealed that this hydroxylation reaction proceeds via a copper (I → III → I) redox mechanism. Application of this reaction to aromatic C-H amination using BnONH2 efficiently afforded the corresponding primary anilines. These reactions show broad scope and good functional group compatibility. Catalytic versions of these transformations are also demonstrated.

• Access to Document (DOI)

Allylic borylation of tertiary allylic alcohols: a divergent and straightforward access to allylic boronates

Kohei Harada, Marina Nogami, Keiichi Hirano, Daisuke Kurauchi, Hisano Kato, Kazunori Miyamoto, Tatsuo Saito, Masanobu Uchiyama

ORGANIC CHEMISTRY FRONTIERS (ROYAL SOC CHEMISTRY)  3 ( 5 ) 565 - 569 2016.05

Accepted,  ISSN  20524110

　View Summary

A facile and divergent synthetic process for converting tertiary allylic alcohols to multiply substituted allylic boronates is reported. This methodology is especially effective for tertiary alcohol substrates, providing the corresponding allylic boronates in moderate to good yields.

• Access to Document (DOI)

Mechanistic Studies on the Generation and Properties of Superelectrophilic Singlet Carbenes from Bis(perfluoroalkanesulfonyl)bromonium Ylides

Kazunori Miyamoto, Susumu Iwasaki, Ryusuke Doi, Taiga Ota, Yufuko Kawano, Junpei Yamashita, Yuuta Sakai, Norihiro Tada, Masahito Ochiai, Satoko Hayashi, Waro Nakanishi, Masanobu Uchiyama

Journal of Organic Chemistry (American Chemical Society)  81 ( 8 ) 3188 - 3198 2016.04

Accepted,  ISSN  00223263

　View Summary

Pyrolysis of bis(perfluoroalkanesulfonyl)bromonium ylides in various olefins results in highly stereospecific formation of cyclopropanes via unimolecular decomposition. Product analysis, kinetic study, substituent effects, and theoretical study revealed the generation of singlet bis(perfluoroalkanesulfonyl)carbenes stabilized by intramolecular coordination of sulfonyl oxygen.

• Access to Document (DOI)

Rhodium-Catalyzed (Perfluoroalkyl)olefination of Acetanilides Leading to Perfluoroalkylated Aromatics

Kohei Harada, Noriyuki Tezuka, Keiichi Hirano, Kazunori Miyamoto, Tatsuo Saito, Masanobu Uchiyama

Chemical and Pharmaceutical Bulletin (Pharmaceutical Society of Japan)  64 ( 10 ) 1442 - 1444 2016

Accepted,  ISSN  00092363

　View Summary

We have developed an efficient Rh-catalyzed (perfluoroalkyl)olefination reaction of acetanilides, which provides a versatile synthetic entry to a range of perfluoroalkylated compounds.

• Access to Document (DOI)

Gold-Catalyzed Cyclization of Alkyne Alcohols: Regioselective Construction of Functionalized 6,6- and 6,7-Bicyclic Ethers

Mio Kubota, Tatsuo Saito, Kazunori Miyamoto, Keiichi Hirano, Chao Wang, Masanobu Uchiyama

CHEMICAL & PHARMACEUTICAL BULLETIN (Pharmaceutical Society of Japan)  64 ( 7 ) 845 - 855 2016

ISSN  00092363

　View Summary

We describe an efficient regioselective formation of six-/seven-membered cyclic ethers based on goldcatalyzed intramolecular hydroalkoxylation. Sequential gold-catalyzed cyclization and palladium-catalyzed cross-coupling reactions afforded 6,6-bicyclic ethers, while reversing the reaction sequence (cross-coupling then cyclization) afforded 6,7-bicyclic ethers. This methodology should provide access to a range of functional polycyclic ethers.

• Access to Document (DOI)

Conjugation between sigma- and pi-Aromaticity in 1-C-Arylated Monocarba-closo-dodecaborate Anions

Otsuka, Mai, Takita, Ryo, Kanazawa, Junichiro, Miyamoto, Kazunori, Muranaka, Atsuya, Uchiyama, Masanobu

Journal of the American Chemical Society 137 ( 48 ) 15082 - 15085 2015.12

Accepted,  ISSN  00027863

　View Summary

Conjugation between σ- and π-aromatic moieties in 1-C-arylated monocarba-closo-dodecaborate anion derivatives 2 has been identified by means of kinetic experimental studies combined with theoretical calculations. We found that the reaction rate of iodination at the 12-B vertex of the carborane anion cage was affected by distal substituents on the benzene ring connected at the antipodal carbon vertex. Hammett and Yukawa-Tsuno plots indicated that substantial resonance effects are involved. Density functional theory calculations enabled detailed interpretation of the electronic interaction.

• Access to Document (DOI)

Dialkylzinc-mediated allylic polyfluoroarylation reaction

Daisuke Kurauchi, Keiichi Hirano, Hisano Kato, Tatsuo Saito, Kazunori Miyamoto, Masanobu Uchiyama

TETRAHEDRON (PERGAMON-ELSEVIER SCIENCE LTD)  71 ( 35 ) 5849 - 5857 2015.07

Accepted,  ISSN  00404020

　View Summary

We present an allylic polyfluoroarylation reaction with broad substrate scope and excellent functional group tolerance, using organozinc reagents under mild conditions. A catalytic amount of triphenylphosphine oxide efficiently promotes iodine-zinc exchange reaction between polyfluoroaryl iodide and dimethylzinc, and the resulting phosphine oxide-activated polyfluoroarylzinc undergoes substitution reaction with allylic halides to afford the corresponding polyfluoroarylated products. (C) 2015 Elsevier Ltd. All rights reserved.

• Access to Document (DOI)

Stereoselective synthesis and reaction of gold(I) (Z)-enethiolates

Kazunori Miyamoto, Masaya Hirobe, Masanobu Uchiyama, Masahito Ochiai

Chemical Communications (Royal Society of Chemistry)  51 ( 37 ) 7962 - 7965 2015.05

Accepted,  ISSN  13597345

　View Summary

Bench-top-storable (Z)-enethiol reagents: gold (Z)-1-decenylthiolates were synthesized stereoselectively in high yields. They are stable upon storage at room temperature without protection from light, and react smoothly with various alkyl halides, α,β-unsaturated ketones, and electron-deficient aryl halides with excellent stereoselectivity.

• Access to Document (DOI)

Unexpected metal-free transformation of gem-dibromomethylenes to ketones under acetylation conditions

Rino Kimura, Yusuke Sawayama, Atsuo Nakazaki, Kazunori Miyamoto, Masanobu Uchiyama, Toshio Nishikawa

Chemistry - An Asian Journal (John Wiley and Sons Ltd)  10 ( 4 ) 1035 - 1041 2015.04

Accepted,  ISSN  18614728

　View Summary

Novel conditions for the transformation of gem-dibromomethylenes to ketones are described. gem-Dibromo compounds were treated with acetic anhydride and triethylamine in dichloromethane/water at room temperature under an air atmosphere to give the corresponding ketones in moderate yields. A radical mechanism is proposed based on experimental results.

• Access to Document (DOI)

Identification of polyethylene glycol-resistant macrophages on stealth imaging in vitro using fluorescent organosilica nanoparticles

Nakamura M., Hayashi K., Nakano M., Kanadani T., Miyamoto K., Kori T., Horikawa K.

ACS Nano 9 ( 2 ) 1058 - 1071 2015.02

ISSN  19360851

　View Summary

An in vitro imaging system to evaluate the stealth function of nanoparticles against mouse macrophages was established using fluorescent organosilica nanoparticles. Surface-functionalized organosilica nanoparticles with polyethylene glycol (PEG) were prepared by a one-step process, resulting in a brush-type PEG layer. A simultaneous dual-particle administration approach enabled us to evaluate the stealth function of nanoparticles with respect to single cells using time-lapse fluorescent microscopic imaging and flow cytometry analyses. Single-cell imaging and analysis revealed various patterns and kinetics of bare and PEGylated nanoparticle uptake. The PEGylated nanoparticles revealed a stealth function against most macrophages (PEG-sensitive macrophages); however, a stealth function against certain macrophages (PEG-insensitive macrophages) was not observed. We identified and characterized the PEG-resistant macrophages that could take up PEGylated nanoparticles at the same level as bare nanoparticles.

• Access to Document (DOI)

Metal-free C-H amination of unactivated hydrocarbons with sulfonylimino-λ³-bromanes generated in situ from (diacetoxybromo)benzene

Miyamoto K., Ota T., Hoque M.M., Ochiai M.

Organic and Biomolecular Chemistry 13 ( 7 ) 2129 - 2133 2015.02

ISSN  14770520

　View Summary

A simple method for direct metal-free C-H amination of unactivated hydrocarbons using easy-handling diacetoxy-λ3-bromane and triflylamide or sulfamate esters was developed. The high 2°/3° regioselectivities and deuterium isotope effects suggest a concerted organonitrenoid transition state, analogous to C-H amination with N-triflylimino-λ3-bromane. This journal is

• Access to Document (DOI)

Reactivity of Hydroxy- and Aquo( hydroxy)-l3-iodane- Crown Ether Complexes

Kazunori Miyamoto, Yukie Yokota, Takashi Suefuji, Kentaro Yamaguchi, Tomoyuki Ozawa, Masahito Ochiai

CHEMISTRY-A EUROPEAN JOURNAL (WILEY-V C H VERLAG GMBH)  20 ( 18 ) 5447 - 5453 2014.04

Accepted,  ISSN  09476539

　View Summary

We have designed a series of hydroxy(aryl)-(3)-iodane-[18]crown-6 complexes, prepared from the corresponding iodosylbenzene derivatives and superacids in the presence of [18]crown-6, and have investigated their reactivities in aqueous media. These activated iodosylbenzene monomers are all non-hygroscopic shelf-storable reagents, but they maintain high oxidizing ability in water. The complexes are effective for the oxidation of phenols, sulfides, olefins, silyl enol ethers, and alkyl(trifluoro)borates under mild conditions. Furthermore, hydroxy-(3)-iodane-[18]crown-6 complexes serve as efficient progenitors for the synthesis of diaryl-, vinyl-, and alkynyl-(3)-iodanes in water. Other less polar organic solvents, such as methanol, acetonitrile, and dichloromethane, are also usable in some cases.

• Access to Document (DOI)

Synthesis of Hypervalent Organo-λ³-bromanes and Their Reactions by Using Leaving Group Ability of λ³-Bromanyl Group

Miyamoto Kazunori

YAKUGAKU ZASSHI (The Pharmaceutical Society of Japan)  134 ( 12 ) 1287 - 1300 2014

ISSN  00316903

　View Summary

Hypervalent organo-λ³-iodanes have attracted great interest in organic synthesis; however, the chemistry of hypervalent organo-λ³-bromanes remains largely unexplored, mainly because of synthetic difficulties. Iodobenzene is readily oxidized by common oxidants such as peracids under mild conditions, whereas bromobenzene is inert. Since the ionization potential of bromobenzene (8.98 eV) is higher than that of iodobenzene (8.69 eV), hypervalent-λ³-bromane would show much higher reactivity. We overcame this problem by using difluoro(aryl)-λ³-bromane (Frohn's reagent), which serves as a pivotal progenitor of various λ³-bromanes including imino-λ³-bromane, cyclopent-1-enyl-λ³-bromane, (<i>E</i>)-β-alkylvinyl-λ³-bromane, and diacetoxy-λ³-bromane. These reagents possess highly unusual reactivity based on the enormously enhanced nucleofugality of the aryl-λ³-bromanyl group.<br>

• Access to Document (DOI)
• Access to Document (DOI)

In situ generation technology of β-butoxycarbonyliodonium ylide: A hypervalent analogue of the Darzens reagent

Miyamoto K., Suzuki M., Suefuji T., Ochiai M.

European Journal of Organic Chemistry  ( 18 ) 3662 - 3666 2013.06

ISSN  1434193X

　View Summary

An ester exchange reaction of β-butoxy-β-acyloxyvinyl- λ3-iodane with lithium bases (ROLi and nBuLi) efficiently generates highly labile monoester iodonium ylide at low temperature. The iodonium ylide generated in situ cleanly undergoes Darzens condensation with aromatic aldehydes to afford trans-epoxy ester selectively. The reactivity of monoester iodonium ylide is investigated. Highly labile mono ester iodonium ylide generated in situ from β-butoxy-β-acyloxyvinyl- λ3-iodane through an ester exchange reaction cleanly undergoes Darzens-type condensation with aromatic aldehydes to afford trans-epoxy ester selectively. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

• Access to Document (DOI)

Time-lapse fluorescence imaging and quantitative single cell and endosomal analysis of peritoneal macrophages using fluorescent organosilica nanoparticles

Nakamura M., Miyamoto K., Hayashi K., Awaad A., Ochiai M., Ishimura K.

Nanomedicine: Nanotechnology, Biology, and Medicine 9 ( 2 ) 274 - 283 2013.02

ISSN  15499634

　View Summary

Fluorescent thiol-organosilica nanoparticles with 100 nm diameter (F-thiol-OS-100) were applied for time-lapse fluorescence imaging. The evaluation of F-thiol-OS-100 for quantitative analysis demonstrated great advantages as compared with quantum dots and organic fluorescent dye. Time-lapse fluorescence imaging of mouse peritoneal macrophages using F-thiol-OS-100 clearly demonstrated cellular uptake, and single cell analysis showed various patterns of uptake kinetics that could be quantitatively evaluated. We also performed quantitative analysis of endosomal uptake and movements in single cells. A correlation between morphologic findings and endosomal uptake and movement over time was also observed and analyzed quantitatively. The F-thiol-OS-100 showed high potential as a new fluorescence marker for time-lapse fluorescence imaging and quantitative single cell functional analysis for nanomedicine development. From the Clinical Editor: In this study the authors report on 100 nm thiol-organosilica nanoparticles as time-lapse flurescent markers. F-thiol-OS-100 proved to be superior to quantum dots and organic flurescent dyes, and enabled quantitative single cell functional analysis. © 2013 Elsevier Inc.

• Access to Document (DOI)