Tohoku University · Chemistry
Professor Hidetoshi Tokuyama's research lab specializes in synthetic organic chemistry, with a focus on the development of novel reaction methodologies for complex molecule synthesis. Key research directions include photoinduced reactions of fullerenes, transition-metal-catalyzed cyclizations (particularly gold- and copper-mediated transformations), and the stereoselective synthesis of nitrogen-containing heterocycles such as indoles and indolizines. The lab also investigates mild and efficient methods for the synthesis of sensitive intermediates like α-amino aldehydes and explores cascade reactions for building molecular complexity.
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoinduced biochemical activity of fullerene carboxylic acidHidetoshi Tokuyama, Shigeru Yamago, Eiichi Nakamura, Takashi Shiraki, and Yukio SugiuraCite this: J. Am. Chem. Soc. 1993, 115, 17, 7918–7919Publication Date (Print):August 1, 1993Publication History Published online1 May 2002Published inissue 1 August 1993https://pubs.acs.org/doi/10.1021/ja00070a064https://doi.org/10.1021/ja00070a064research-articleACS PublicationsRequest reuse permissionsAr
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTRadical Cyclization of 2-Alkenylthioanilides: A Novel Synthesis of 2,3-Disubstituted IndolesHidetoshi Tokuyama, Tohru Yamashita, Matthew T. Reding, Yosuke Kaburagi, and Tohru FukuyamaView Author Information Graduate School of Pharmaceutical Sciences The University of Tokyo CREST, Japan Science and Technology Corporation (JST) 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan Cite this: J. Am. Chem. Soc. 1999, 121, 15, 3791–3792Publication Date (Web)
Herein, we review copper-mediated aromatic amination reactions including the classical Ullmann coupling and the recently developed mild aryl amination with an effective ligand as well as the C-H amination reaction. Several applications of intramolecular aryl amination to the syntheses of natural products demonstrate the general applicability of the reaction.
Reduction of ethanethiol esters of α-amino acids to α-amino aldehydes by triethylsilane and catalytic palladium-on-carbon is described. α-Amino aldehydes with Boc, Cbz, or Fmoc protection could be obtained without racemization in high yield.
‘Rhaz'zmatazz: A total synthesis of (−)-rhazinilam and the first asymmetric total synthesis of (−)-rhazinicine were accomplished by using constructing the indolizinone core through the gold-catalyzed cyclization of a fully elaborated linear ynamide. The scope and generality of this cascade reaction for the construction of highly substituted indolizinones were also investigated. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such mat
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthetic Chemistry with Fullerenes. Photooxygenation of OlefinsHidetoshi Tokuyama and Eiichi NakamuraCite this: J. Org. Chem. 1994, 59, 5, 1135–1138Publication Date (Print):March 1, 1994Publication History Published online1 May 2002Published inissue 1 March 1994https://pubs.acs.org/doi/10.1021/jo00084a036https://doi.org/10.1021/jo00084a036research-articleACS PublicationsRequest reuse permissionsArticle Views739Altmetric-Citations85LEARN ABOUT THESE ME
Development of indole synthesis by tin-mediated radical cyclization of o-alkenylphenyl isocyanide is described. Upon heating o-alkenylphenyl isocyanide in the presence of tri-n-butyltin hydride and AIBN, 2-stannyl-3-substituted indole was formed via 5-exo-trig cyclization of the imidoyl radical intermediate. After acidic workup, 3-substituted indoles were isolated. For substrates bearing simple alkyl groups, a substantial amount of tetrahydroquinoline derivatives were generated through 6-endo-tr
Treatment of ethanethiol esters with triethylsilane and palladium on carbon at ambient temperature furnished aldehydes. In addition, a variety of ketones have been prepared by a palladium-catalyzed reaction of ethanethiol esters with organozinc reagents. Various functional groups, including esters, ketones, aromatic halides and aldehydes, tolerate both transformation reactions. These novel reactions can also be applied to the synthesis of alpha-amino aldehyde and alpha-amino ketone derivatives u
A highly efficient total synthesis of dictyodendrins A-E was accomplished. The synthesis features a novel benzyne-mediated one-pot indoline formation/cross-coupling sequence for the construction of a highly substituted key indoline intermediate. Peripheral substituents were introduced onto this intermediate in a modular fashion to complete the total synthesis of dictyodendrins A-E.
N-Unprotected 2-iodoindoles are synthesized by treatment of 2-stannylindoles with iodine, which in turn are prepared by tin-mediated radical cyclization of 2-alkenylphenylisocyanides. Palladium-catalyzed coupling reactions of N-unprotected 2-iodoindoles with terminal acetylenes, terminal olefins, carbonylation, and the Suzuki coupling reaction with phenyl borate proceed smoothly to furnish the corresponding 2,3-disubstituted indoles in good to excellent yields.
A cationic fluorescent nanogel thermometer based on thermo-responsive N-isopropylacrylamide and environment-sensitive benzothiadiazole was developed with a new azo compound bearing imidazolium rings as the first cationic radical initiator. This cationic fluorescent nanogel thermometer showed an excellent ability to enter live mammalian cells in a short incubation period (10 min), a high sensitivity to temperature variations in live cells (temperature resolution of 0.02-0.84 °C in the range 20-40
The key step in this total synthesis of (-)-acetylaranotin is the efficient formation of the characteristic dihydrooxepine ring from cyclohexenone through an unusual vinylogous Rubottom oxidation and a regioselective Baeyer-Villiger oxidation. (-)-Acetylaranotin is obtained in 22 steps from commercially available L-Cbz-tyrosine (Cbz=benzyloxycarbonyl).
A novel transformation of primary amines to the corresponding N-monoalkylhydroxylamines is described. The three-step protocol involves selective mono-cyanomethylation of primary amines, regioselective formation of nitrones by m-CPBA oxidation, and hydroxylaminolysis of the nitrones with hydroxylamine hydrochloride. The method is applicable for a wide range of primary amines, including alkyl, benzyl, and chiral.
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