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Shibaura Institute of Technology
College of Engineering, Department of Applied Chemistry, College of Engineering Materials Science Course Department of Applied Chemistry
Research funding number


Yuki Kikuchi, Chisato Nakamura, Mizuki Matsuoka, Rina Asami, Osamu Kitagawa
Journal of Organic Chemistry   84 8112-8120   Jun 2019
© 2019 American Chemical Society. In the presence of (S,S)-Trost ligand and (allyl-Pd-Cl)2 catalyst, the reaction of allyl acetate with the anionic species prepared from various N-(2-tert-butylphenyl)sulfonamides and NaH proceeded in an enantiosel...
Asumi Iida, Mizuki Matsuoka, Hiroshi Hasegawa, Nicolas Vanthuyne, Daniel Farran, Christian Roussel, Osamu Kitagawa
Journal of Organic Chemistry   84 3169-3175   Mar 2019
© 2019 American Chemical Society. The fluorine atom is the second smallest atom; nevertheless, the ortho-fluoro group may lead to stable N-aryl atropisomers when the steric demand of the flanking substituents is large enough. 2-Alkyl-3-(2-fluoroph...
Takuma Hosaka, Tomomi Imai, Alicja Wzorek, Magdalena Marcinkowska, Anna Kolbus, Osamu Kitagawa, Vadim A. Soloshonok, Karel D. Klika
Amino Acids   51 283-294   Feb 2019
© 2018, Springer-Verlag GmbH Austria, part of Springer Nature. α-Amino acids (α-AAs) are in extremely high demand in nearly every sector of the food and health-related chemical industries and continue to be the subject of intense multidisciplinary...
Tomomi Imai, Erina Niijima, Shumpei Terada, Alicja Wzorek, Vadim A. Soloshonok, Akiko Hori, Osamu Kitagawa
CrystEngComm   21 3385-3389   Jan 2019
© The Royal Society of Chemistry 2019. In the crystals prepared from racemic axially chiral 3-(ortho-halophenyl)-2-methylquinazolin-4-one derivatives, the formation of intermolecular halogen bonding (CO⋯X) between the carbonyl oxygen and ortho-hal...
Mizuki Matsuoka, Asumi Iida, Osamu Kitagawa
Synlett   29 2126-2130   May 2018
© Georg Thieme Verlag Stuttgart - New York. 2-Ethylquinazolin-4-one derivatives bearing various ortho -substituted phenyl groups were revealed to possess a stable C-N axially chiral structure at ambient temperature. The reactions of alkyl halides ...
Yumiko Iwasaki, Ryuichi Morisawa, Satoshi Yokojima, Hiroshi Hasegawa, Christian Roussel, Nicolas Vanthuyne, Elsa Caytan, Osamu Kitagawa
Chemistry - A European Journal   24 4453-4458   Mar 2018
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim N-Aryl-N-methyl-2-tert-butyl-6-methylaniline derivatives exhibit a rotationally stable N−C axially chiral structure and the rotational barriers around an N−C chiral axis increased with the increa...
Jianlin Han, Osamu Kitagawa, Alicja Wzorek, Karel D. Klika, Vadim A. Soloshonok
Chemical Science   9 1718-1739   Feb 2018
© The Royal Society of Chemistry 2018. Herein we report on the well-documented, yet not widely known, phenomenon of the self-disproportionation of enantiomers (SDE): the spontaneous fractionation of scalemic material into enantioenriched and -depl...
Nobutaka Ototake, Osamu Kitagawa
Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry   76 575-583   Jan 2018
© 2018 Society of Synthetic Organic Chemistry. All rights reserved. Amide C-N bond in 2,6-di-tert-butylanilides has a high rotational barrier and the individual amide rotational isomers can be isolated at ambient temperature. These anilides have b...
Shumpei Terada, Motohiro Hirai, Ayaka Honzawa, Osamu Kitagawa, Angelika Kamizela, Alicja Wzorek, Vadim A. Soloshonok
Chemistry - A European Journal   23 14631-14638   Oct 2017
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The major breakthrough reported in this work is the discovery of likely halogen bond-driven self-disproportionation of enantiomers (SDE). Taking into account that the halogen-bonding interactions...
Mizuki Matsuoka, Mitsuhiro Goto, Alicja Wzorek, Vadim A. Soloshonok, Osamu Kitagawa
Organic Letters   19 2650-2653   May 2017
© 2017 American Chemical Society. The reactions of various alkyl halides with the metallo enamines generated from racemic and optically pure N-C axially chiral mebroqualone derivatives were found to proceed with a synthetically attractive stereoch...
Tomoyuki Yamada, Shiori Tsukagoshi, Osamu Kitagawa
Tetrahedron Letters   58 317-320   Jan 2017
© 2016 Elsevier Ltd The reaction of methyl iodide with an anilide anion prepared from 2,4,6-tri-tert-butylanilide and NaH in CH3CN gave N-methyl anilide (N-alkylation product) as a major product, while in the reaction of benzyl bromide with the an...
Motohiro Hirai, Shumpei Terada, Hiroaki Yoshida, Kenki Ebine, Tomoaki Hirata, Osamu Kitagawa
Organic Letters   18 5700-5703   Nov 2016
© 2016 American Chemical Society. In the presence of (R)-DTBM-SEGPHOS-Pd(OAc)2 catalyst, treatment of various 3-(2,6-dibromophenyl)quinazolin-4-ones with NaBH4 gave optically active N-C axially chiral quinazolinone (mebroqualone) derivatives throu...
Mitsuhiro Goto, Kaori Tateishi, Kenki Ebine, Vadim A. Soloshonok, Christian Roussel, Osamu Kitagawa
Tetrahedron Asymmetry   27 317-321   May 2016
© 2016 Elsevier Ltd. All rights reserved. Mixtures of enantiomerically pure (S)-N-formyl-1-phenylethyamine and various racemic N-formyl-1-arylethylamine derivatives, when submitted to achiral medium pressure liquid chromatography, afforded elution...
Tomoaki Hirata, Isao Takahashi, Yuya Suzuki, Hiroaki Yoshida, Hiroshi Hasegawa, Osamu Kitagawa
Journal of Organic Chemistry   81 318-323   Jan 2016
© 2015 American Chemical Society. N-C axially chiral phenanthridin-6-one derivatives bearing various ortho-substituted phenyl groups on the nitrogen atom were enantioselectively prepared through (R)-DTBM-SEGPHOS-Pd(OAc)2-catalyzed intramolecular B...
Yudai Morimoto, Satoshi Shimizu, Ayano Mokuya, Nobutaka Ototake, Akio Saito, Osamu Kitagawa
Tetrahedron   72 5221-5229   Jan 2016
© 2015 Elsevier Ltd In the presence of (R)-SEGPHOS-PdCl2catalyst, 5-endo-hydroaminocyclization of various 2-(tert-butyl)-N-(2-ethynylphenyl)anilines proceeds enantioselectively to afford optically active N–C axially chiral N-(2-tert-butylphenyl)in...
Yuya Suzuki, Masato Kageyama, Ryuichi Morisawa, Yasuo Dobashi, Hiroshi Hasegawa, Satoshi Yokojima, Osamu Kitagawa
Chemical Communications   51 11229-11232   Jul 2015
© 2015 The Royal Society of Chemistry. Optically active atropisomeric N-(2,5-di-tert-butylphenyl)-1,2,3,4-tetrahydroquinoline with an N-C chiral axis was prepared via a catalytic enantioselective reaction. The addition of methane sulfonic acid to ...
Yuya Suzuki, Jianlin Han, Osamu Kitagawa, José Luis Aceña, Karel D. Klika, Vadim A. Soloshonok
RSC Advances   5 2988-2993   Jan 2015
© The Royal Society of Chemistry 2015. This work explores the self-disproportionation of enantiomers (SDE) of chiral amides via achiral, gravity-driven column chromatography as typically used in laboratory settings. The major findings of this work...
Yuya Suzuki, Isao Takahashi, Yasuo Dobashi, Hiroshi Hasegawa, Christian Roussel, Osamu Kitagawa
Tetrahedron Letters   56 132-135   Jan 2015
© 2014 Elsevier Ltd. All rights reserved. The rotational barrier around the N-C chiral axis in N-(2-tert-butylphenyl)-3,4-dihydrobenzoquinolin-2-one was found to be 6 kcal/mol lower than that in N-(2-tert-butylphenyl)-3,4-dihydroquinolin-2-one. X-...
Isao Takahashi, Yuya Suzuki, Osamu Kitagawa
Organic Preparations and Procedures International   46 1-23   Jan 2014
Kaori Tateishi, Shiori Tsukagoshi, Tsuyoshi Nakamura, Shotaro Watanabe, Vadim A. Soloshonok, Osamu Kitagawa
Tetrahedron Letters   54 5220-5223   Sep 2013
We report here the theoretical design and proof of principle of the first example of a conceptually new approach for the preparation of enantiomerically pure compounds from the racemates by chiral initiator-induced Self-Disproportionation of Enant...
Shiori Tsukagoshi, Nobutaka Ototake, Yusuke Ohnishi, Mayu Shimizu, Osamu Kitagawa
Chemistry - A European Journal   19 6845-6850   May 2013
Herein, we report a unique structural property of 2,4,6-tri-tert- butylanilide, which can be separated into its amide rotamers at room temperature. Interconversion between the rotamers of anilide enolates occurs readily at room temperature and the...
Nobutaka Ototake, Isao Takahashi, Shiori Tsukagoshi, Tatsuki Maeda, Osamu Kitagawa
Tetrahedron   69 1013-1016   Jan 2013
Z-Rotamers of several 2,4,6-tri-tert-butylanilides slowly isomerize at rt in CDCl3 to E-rotamers, yielding equilibrium mixtures of Z- and E-rotamers after standing for 1 week. The equilibrium ratios between the anilide rotamers in the solution dep...
Isao Takahashi, Fumika Morita, Shunsuke Kusagaya, Haruhiko Fukaya, Osamu Kitagawa
Tetrahedron Asymmetry   23 1657-1662   Dec 2012
In the presence of an (R)-MOP-Pd2(dba)3 catalyst, the reaction of ortho-tert-butylaniline with 2-bromophenyl arylethynyl ketone proceeded via a tandem amination (1,4-addition of aniline to an ynone and subsequent intramolecular Buchwald-Hartwig am...
Naomi Suzumura, Masato Kageyama, Daichi Kamimura, Takahiro Inagaki, Yasuo Dobashi, Hiroshi Hasegawa, Haruhiko Fukaya, Osamu Kitagawa
Tetrahedron Letters   53 4332-4336   Aug 2012
The rotational barriers in axially chiral quinolin-2-one and quinazolin-2-one possessing N-(ortho-tert-butyl)phenyl group were found to significantly increase in comparison with those of corresponding dihydroquinolin-2-one and dihydroquinazolin-2-...
Vadim A. Soloshonok, Christian Roussel, Osamu Kitagawa, Alexander E. Sorochinsky
Chemical Society Reviews   41 4180-4188   Jun 2012
This tutorial review describes the self-disproportionation of enantiomers (SDE) of chiral, non-racemic compounds, subjected to chromatography on an achiral stationary phase using an achiral eluent, which leads to the substantial enantiomeric enric...
Tsuyoshi Nakamura, Kaori Tateishi, Shiori Tsukagoshi, Saori Hashimoto, Shotaro Watanabe, Vadim A. Soloshonok, José Luis Aceña, Osamu Kitagawa
Tetrahedron   68 4013-4017   May 2012
Efficient self-disproportionation of enantiomers of several non-racemic chiral amines was achieved through conversion to N-acetamides and subsequent MPLC using an achiral column. The MPLC of these non-racemic N-acetamide derivatives gave the chart...
Masashi Takahashi, Osamu Kitagawa
Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry   69 985-993   Sep 2011
Atropisomeric compounds due to rotational restriction around an N-C bond have received much attention recently as novel chiral molecules. However, catalytic enantioselective synthesis of such N-C axially chiral compounds has not so far been report...
Yusuke Ohnishi, Masahi Sakai, Shouta Nakao, Osamu Kitagawa
Organic Letters   13 2840-2843   Jun 2011
Interconversion between the separable 2,4,6-tri-tert-butylanilide rotamers was found to easily occur through formation of the lithium enolate. Protonation of the anilide enolate gave the anilide rotamer mixture of E-major. On the other hand, react...
Masashi Nakamura, Isao Takahashi, Shunsuke Yamada, Yasuo Dobashi, Osamu Kitagawa
Tetrahedron Letters   52 53-55   Jan 2011
Intramolecular Diels-Alder reactions of various N-allyl 2-furoyl amides with different substituents on the nitrogen atom were investigated. The reaction of amides having bulky substituents proceeded at a faster rate than the analogs whose substitu...
Nobutaka Ototake, Yudai Morimoto, Ayano Mokuya, Haruhiko Fukaya, Yasuo Shida, Osamu Kitagawa
Chemistry - A European Journal   16 6752-6755   Jun 2010
(Chemical Equation Presented) A pivotal role: In the presence of (R)-(-)-5,5′-bis[di(3,5-di-tert-butyl-4-methoxyphenyl)phosphino]-4, 4′-bi-1,3-benzodioxole-PdCl2 [(R)-SEGPHOS-PdCl2], 5-endo-hydroaminocyclization of achiral ortho-alkynylanilines pr...
Masashi Takahashi, Hajime Tanabe, Tsuyoshi Nakamura, Daisuke Kuribara, Toshiyuki Yamazaki, Osamu Kitagawa
Tetrahedron   66 288-296   Jan 2010
In the presence of (R)-SEGPHOS-Pd(OAc)2 catalyst, the intramolecular N-arylation of ortho-tert-butyl-NH-anilides possessing an iodophenyl group proceeded in a highly enantioselective manner (89-98% ee) to give optically active atropisomeric lactam...
Nobutaka Ototake, Masashi Nakamura, Yasuo Dobashi, Haruhiko Fukaya, Osamu Kitagawa
Chemistry - A European Journal   15 5090-5095   May 2009
By using Pd chemistry, a highly selective stereodivergent synthesis of separable amide rotamers was achieved. Allylation of 2,4,6-tri-tert-bu- tylanilides using a π-allyl-Pd catalyst gave N-allylated anilides with moderate-to-excellent Z-rotamer s...
Nobutaka Ototake, Takeo Taguchi, Osamu Kitagawa
Tetrahedron Letters   49 5458-5460   Sep 2008
Separable amide rotamers were prepared with moderate to excellent Z-selectivities by N-allylation of 2,4,6-tri-tert-butyl-NH-anilides using a π-allyl-Pd catalyst. The present allylation proceeded through a unique mechanism involving O-allylation a...
Osamu Kitagawa, Daisuke Kurihara, Hajime Tanabe, Taichi Shibuya, Takeo Taguchi
Tetrahedron Letters   49 471-474   Jan 2008
An atropisomeric lactam which was prepared with high enantioselectivity by catalytic asymmetric intramolecular N-arylation, was efficiently converted to synthetic intermediates for NET inhibitors through highly diastereoselective α-alkylation foll...
Highly Enantioselctive Synthesis of Atropisomeric Lactams through Catalytic Asymmetric Buchwald-Hartwig Amination
Osamu Kitagawa, Masatoshi Yoshikawa, Hajime Tanabe, Tomofumi Morita, Masashi Takahashi, Yasuo Dobashi, Takeo Taguchi
Journal of the American Chemical Society   128 12923-12931   Oct 2006
In the presence of (R)-DTBM-SEGPHOS-Pd(OAc)2 catalyst, N-arylation (aromatic amination) of various o-tert-butylanilides with p-iodonitrobenzene proceeds with high enantioselectivity (88-96% ee) to give atropisomeric N-(p-nitrophenyl)anilides havin...
Osamu Kitagawa, Shinichi Matsuo, Kanako Yotsumoto, Takeo Taguchi
Journal of Organic Chemistry   71 2524-2527   Mar 2006
In the presence of the Trost ligands-Pd catalysts, N-monoallylation of bis(2,4,6-triisopropylbenzne)sulfonylamides derived from meio-1,2-diamines proceeds with good to excellent enantioselectivity (85-96% ee) to give asymmetric desymmetrization pr...
Osamu Kitagawa, Masashi Takahashi, Masatoshi Yoshikawa, Takeo Taguchi
Journal of the American Chemical Society   127 3676-3677   Mar 2005
In the presence of (R)-DTBM-SEGPHOS-Pd(OAc)2 catalyst, N-arylation of ortho-tert-butyl-NH-anilides with 4-nitroiodobenzene proceeds with high enantioselectivity (89-95% ee) to give optically active atropisomeric anilides possessing N-C chiral axis...
Osamu Kitagawa, Kanako Yotsumoto, Mitsuteru Kohriyama, Yasuo Dobashi, Takeo Taguchi
Organic Letters   6 3605-3607   Sep 2004
(Chemical Equation Presented) N-Monoallylation of meso-vicinal diamine bistrisylamides using a chiral π-allyl-Pd catalyst proceeded in an enantioselective manner (up to 90% ee) to give desymmetrization products in good yields. The product was conv...
Osamu Kitagawa, Shinsaku Miyaji, Chiseko Sakuma, Takeo Taguchi
Journal of Organic Chemistry   69 2607-2610   Apr 2004
Treatment of 1-diethylphosphonyl- or 1-phenyl-sulfonyl-2-(iodomethyl)cyclopropane-l-carboxylate with Et3B leads to an unsymmetrical allylated active methine radical species that gives functionalized cyclopentane derivatives with high stereoselecti...
Osamu Kitagawa, Masashi Takahashi, Mitsuteru Kohriyama, Takeo Taguchi
Journal of Organic Chemistry   68 9851-9853   Dec 2003
N-Allylation of o-tert-butyl anilides derived from o-tert-butyl aniline and (S)-lactic acid or (S)-mandelic acid proceeded with high diastereoselectivity in the presence of a (BINAP)Pd-π-allyl catalyst to give atropisomeric N-allyl o-tert-butyl an...
Akio Saito, Midori Okada, Yuko Nakamura, Osamu Kitagawa, Hiroaki Horikawa, Takeo Taguchi
Journal of Fluorine Chemistry   123 75-80   Sep 2003
Carbocyclization of terminally difluorinated 3-butenyl active methine compounds 1a-1e proceeded through the 5- endo mode, upon treating with SnCl4 and triethylamine to give fluorocyclopentene derivatives 3a-3e. Iodocarbocyclization of dimethyl 2-(...
Osamu Kitagawa, Shinsaku Miyaji, Yoichiro Yamada, Hiroki Fujiwara, Takeo Taguchi
Journal of Organic Chemistry   68 3184-3189   Apr 2003
Treatment of N-tosyliodoaziridine derivatives with Et 3 B efficiently produces various azahomoallyl radical (2-akenylamidyl radical) species which give oxygen-functionalized pyrrolidine derivatives through iodine atom transfer [3 + 2] cycloadditio...
Osamu Kitagawa, Mitsuteru Kohriyama, Takeo Taguchi
Journal of Organic Chemistry   67 8682-8684   Nov 2002
Catalytic asymmetric N-allylation reaction of ortho-tert-butylanilide derivatives with diallyl carbonate proceeds in the presence of tol-BINAP-Pd catalyst to give chiral N-allyl ortho-tert-butylanilides of 32-44%ee in excellent chemical yields (≥ ...
Osamu Kitagawa, Yoichiro Yamada, Atsushi Sugawara, Takeo Taguchi
Organic Letters   4 1011-1013   Mar 2002
(equation presented) Radical cascade reaction with various 1,4-dienes and 1,4-enynes using dimethyl 2-(iodomethyl)cyclopropane-1,1-dicarboxylate as a homoallyl radical precursor smoothly proceeds through an iodine atom transfer mechanism to give f...
Osamu Kitagawa, Yoichiro Yamada, Hiroki Fujiwara, Takeo Taguchi
Journal of Organic Chemistry   67 922-927   Feb 2002
Radical iodine atom transfer [3 + 2] cycloaddition with various alkenes using dimethyl 2-(iodomethyl) cyclopropane-1,1-dicarboxylate and 1,1-bis(phenylsulfonyl)-2-(iodomethyl)cyclopropane as new precursors of a homoallyl radical species smoothly p...
Iodocarbocyclization and Intramolecular Carbometalation Strategies for Carbocycles.
My Favorite Organic Synthesis   202-203   2002
O. Kitagawa, Y. Yamada, H. Fujiwara, T. Taguchi
Angewandte Chemie - International Edition   40 3865-3867   Oct 2001
Functionalized pyrrolidine derivatives are accessible in good yields by radical iodine-transfer [3+2] cycloaddition of electron-rich alkenes with azahomoallyl radicals [Eq. (1)], which were generated by treating iodoaziridine derivatives with radi...
Osamu Kitagawa, Shu Ichi Momose, Yoichiro Yamada, Motoo Shiro, Takeo Taguchi
Tetrahedron Letters   42 4865-4868   Jul 2001
Treatment of chiral α-benzyloxy- or α-propargyloxycarboxamide with tert-BuLi gave β-hydroxycarboxamides (aldol derivatives) in high optical purity through the formation of α-lithiated ethers and the subsquent 1,2-Wittig rearrangement. © 2001 Elsev...
Osamu Kitagawa, Hiroki Fujiwara, Takeo Taguchi
Tetrahedron Letters   42 2165-2167   Mar 2001
Radical iodine atom transfer [3+2]-cycloaddition with various alkenes using dimethyl 2-(iodomethyl)cyclopropane-1,1-dicarboxylate as a new precursor of homoallyl radical species smoothly proceeds to give functionalized cyclopentane derivatives in ...