Takeshi Hanamoto

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Organization: Saga University

Department: Department of Chemistry and Applied Chemistry

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Chemicals
References

Facile synthesis of (E)-β-(trifluoromethyl)styrenes from halothane (HCFC-123B1)

Co-reporter:Kensuke Hirotaki, Genyu Kawazoe, Takeshi Hanamoto

Journal of Fluorine Chemistry 2015 Volume 171() pp:169-173

Publication Date(Web):March 2015

DOI:10.1016/j.jfluchem.2014.07.018

•We achieved the synthesis of (E)-β-(trifluoromethyl)styrenes.•All reagents used here were easily available and inexpensive.•The products showed high to excellent stereoselectivity.A practical and convenient synthesis of (E)-β-(trifluoromethyl)styrenes has been achieved by the reaction of commercially available halothane (HCFC-123B1) and hydrazones prepared in advance in situ, in the presence of 1,2-ethylenediamine and a catalytic amount of CuCl2·2H2O at room temperature. The products showed acceptable to high yields and high to excellent stereoselectivity. This handy synthetic method provided easy access to a variety of (E)-β-(trifluoromethyl)styrenes.A practical and convenient synthesis of (E)-β-(trifluoromethyl)styrenes has been achieved by the reaction of halothane (HCFC-123B1) and hydrazones in the presence of 1,2-ethylenediamine and a catalytic amount of CuCl2·2H2O at room temperature.

Difluoromethyl vinyl sulfonium salt: a one-pot access to difluoromethyl-containing cyclopropanes

Co-reporter:Takuya Ishikawa, Noritaka Kasai, Yasunori Yamada, Takeshi Hanamoto

Tetrahedron 2015 Volume 71(Issue 8) pp:1254-1260

Publication Date(Web):25 February 2015

DOI:10.1016/j.tet.2014.12.102

We demonstrate the first preparation of difluoromethyl (CF2H) vinyl sulfonium salt as a new difluoromethylated building block, followed by its application to the synthesis of CF2H-containing cyclopropanes in one step. The salt itself is readily prepared from 3-bromo-3,3-difluoropropene in three steps, in high overall yields, and is stable. A wide range of active methylene compounds participated in the cyclopropanation reaction using this salt, providing the corresponding products in high-to-excellent yields.

TiF4-Mediated Regioselective Cycloaddition of 2-(Trifluoromethyl)-N-tosylaziridine to Nitriles

Co-reporter:Michiya Yoshiki, Rie Ishibashi, Yasunori Yamada, and Takeshi Hanamoto

Organic Letters 2014 Volume 16(Issue 21) pp:5509-5511

Publication Date(Web):October 29, 2014

DOI:10.1021/ol502331a

We report the first [3 + 2] cycloaddition of 2-(trifluoromethyl)-N-tosylaziridine to nitriles using TiF4 as an effective Lewis acid under mild reaction conditions. The reaction proceeded smoothly and afforded the corresponding 4-(trifluoromethyl)-1,3-imidazolines in good yields and with excellent regioselectivity.

Diethylzinc-Promoted Synthesis of Trifluromethyl-Containing Tryptamine Analogues from Indoles and 2-Trifluromethyl-N-(4-Toluenesulfonyl)-Aziridine

Co-reporter:Kensuke Hirotaki;Dr. Yasunori Yamada ;Dr. Takeshi Hanamoto

Asian Journal of Organic Chemistry 2014 Volume 3( Issue 3) pp:285-288

Publication Date(Web):

DOI:10.1002/ajoc.201300286

Abstract

Incorporation of fluorine atoms into biologically active organic molecules often causes enhancement of activity, stability, and solubility, as well as reduction of toxicity. Tryptamine derivatives are known for important medicines concerning our mental health. Therefore, fluorinated tryptamine derivatives could be promising medicinal candidates for pharmaceutical chemistry. We have already reported the regioselective ring-opening reaction of 2-CF₃-N-Ts-aziridine (Ts=4-toluenesulfonyl) with some nucleophiles. If this ring-opening reaction proceeds smoothly at the C3 position of indoles, it could provide a solution for the synthesis of CF₃-containing tryptamine analogues. We examined the diethylzinc-promoted direct C3 alkylation of indoles with 2-CF₃-N-Ts-aziridine under basic conditions. We have developed the synthesis of CF₃-tryptamine from 2-CF₃-N-Ts-aziridines and indoles by using diethylzinc as a base with excellent yields and complete regioselectivity.

Synthesis of mono-fluorinated functionalized cyclopropanes and aziridines using the α-fluorovinyl diphenyl sulfonium salt

Co-reporter:Kensuke Hirotaki, Yui Takehiro, Ryo Kamaishi, Yasunori Yamada and Takeshi Hanamoto

Chemical Communications 2013 vol. 49(Issue 72) pp:7965-7967

Publication Date(Web):31 Jul 2013

DOI:10.1039/C3CC44519D

The α-fluorovinyl diphenyl sulfonium salt 1 is attractive due to its high potential for the synthesis of mono-fluorinated cyclopropanes and aziridines as useful three-membered rings. The synthetically useful salt 1 is readily prepared from α-fluorovinyl phenyl sulfide and diphenyl iodonium salt in one step.

Synthesis of 2-Aryl-3-fluoro-5-silylthiophenes via a Cascade Reactive Sequence

Co-reporter:Kensuke Hirotaki and Takeshi Hanamoto

Organic Letters 2013 Volume 15(Issue 6) pp:1226-1229

Publication Date(Web):March 1, 2013

DOI:10.1021/ol400141y

2-Aryl-3-fluoro-5-silylthiophenes were readily prepared only in two steps from 2-bromo-3,3,3-trifluoropropene in good yields. These transformations include the first successful SN2′-type reaction of 2-bromo-3,3,3-trifluoropropene and benzylthiols and [2,3]sigmatropic rearrangement of 2-bromo-3,3-difluoroallyl benzyl sulfide.

Regioselective ring-opening reaction of 2-trifluoromethyl-N-tosylaziridine with some nucleophiles under basic conditions

Co-reporter:Yui Takehiro, Kensuke Hirotaki, Chihomi Takeshita, Hiroshi Furuno, Takeshi Hanamoto

Tetrahedron 2013 69(35) pp: 7448-7454

Publication Date(Web):

DOI:10.1016/j.tet.2013.06.044

AgSbF6-Promoted Cycloaddition Reaction of 2-Trifluoromethyl-N-tosylaziridine with Aldehydes

Co-reporter:Ryoko Maeda, Rie Ishibashi, Ryo Kamaishi, Kensuke Hirotaki, Hiroshi Furuno, and Takeshi Hanamoto

Organic Letters 2011 Volume 13(Issue 23) pp:6240-6243

Publication Date(Web):October 28, 2011

DOI:10.1021/ol202697y

2-Trifluoromethyl-N-tosylaziridine reacted with various aldehydes in the presence of a catalytic amount of AgSbF6 to provide the corresponding cis-4-trifluoromethyl-2-substituted-N-tosyl-1,3-oxazolidines with excellent regio- and stereoselectivity.

Mizoroki–Heck Reaction of (1-Fluorovinyl)methyldiphenylsilane with Aryl Iodides

Co-reporter:Kensuke Hirotaki and Takeshi Hanamoto

The Journal of Organic Chemistry 2011 Volume 76(Issue 20) pp:8564-8568

Publication Date(Web):September 29, 2011

DOI:10.1021/jo201720x

The Mizoroki-Heck reaction of (1-fluorovinyl)methyldiphenylsilane with a variety of aryl iodides was accomplished under the conditions composing Pd(OAc)2, Ag2CO3 and MS 4 Å in 1,4-dioxane to give the corresponding (E)-β-aryl-(α-fluorovinyl)methyldiphenylsilanes with excellent stereoselectivity.

Preparation and Reactions of (β-Trifluoromethyl)vinyl Sulfonium Salt

Co-reporter:Ryoko Maeda, Kyoko Ooyama, Ryoko Anno, Masahiro Shiosaki, Takayuki Azema and Takeshi Hanamoto

Organic Letters 2010 Volume 12(Issue 11) pp:2548-2550

Publication Date(Web):May 10, 2010

DOI:10.1021/ol100768s

(β-Trifluoromethyl)vinyl sulfonium salt as a novel three-carbon fluorinated building block was conveniently prepared from easily available (β-trifluoromethyl)vinyl sulfide and diphenyl iodonium salt in excellent yield. This easily handled crystalline reagent displayed two types of useful transformation involving aziridination and vinylation to afford the corresponding trifluoromethylated compounds in excellent yields.

Property and Reactivity of Fluoro(silyl)acetylenes and Fluoro(stannyl)acetylenes

Co-reporter:Masahiro Shiosaki, Masashi Unno, and Takeshi Hanamoto

The Journal of Organic Chemistry 2010 Volume 75(Issue 23) pp:8326-8329

Publication Date(Web):November 10, 2010

DOI:10.1021/jo1018602

Fluoro(silyl)acetylenes and fluoro(stannyl)acetylenes underwent a radical addition reaction of THF to furnish the corresponding fluorinated cyclic ethers in moderate to good yields. These intriguing addition reaction proved to proceed via a radical reaction mechanism.

β-Trifluoromethyl-α-functionalized-vinyl sulfides as a potential synthetic intermediate

Co-reporter:Takeshi Hanamoto, Ryoko Anno, Kenji Yamada, Kousuke Ryu, Ryoko Maeda, Kazuya Aoi, Hiroshi Furuno

Tetrahedron 2009 65(14) pp: 2757-2765

Publication Date(Web):

DOI:10.1016/j.tet.2009.01.097

Palladium catalyzed cross-coupling reaction of 5-tributylstannyl-4-fluoropyrazole

Co-reporter:Takeshi Hanamoto, Yukinori Koga, Eisaku Kido, Toshio Kawanami, Hiroshi Furuno and Junji Inanaga

Chemical Communications 2005 (Issue 15) pp:2041-2043

Publication Date(Web):01 Mar 2005

DOI:10.1039/B419329F

The palladium catalyzed cross-coupling reactions of aryl iodides and 5-tributylstannyl-4-fluoropyrazole prepared from fluoro(tributylstannyl)acetylene proceeded smoothly giving the corresponding 5-aryl-4-fluoropyrazole in good yields.

Crystal Structure of a Dewar Benzene Derivative Formed from Fluoro(triisopropylsilyl)acetylene

Co-reporter:Takeshi Hanamoto Dr.;Yukinori Koga;Toshio Kawanami;Hiroshi Furuno Dr.;Junji Inanaga Dr.

Angewandte Chemie 2004 Volume 116(Issue 27) pp:

Publication Date(Web):29 JUN 2004

DOI:10.1002/ange.200454174

Spontane Trimerisierung von Fluor(triisopropylsilyl)acetylen, das aus 1,1-Difluorethylen in einem Schritt erhalten wird, liefert das entsprechende fluorierte Dewar-Benzol-Derivat, dessen Struktur durch Röntgenbeugung ermittelt wurde (siehe Bild).

Crystal Structure of a Dewar Benzene Derivative Formed from Fluoro(triisopropylsilyl)acetylene

Co-reporter:Takeshi Hanamoto Dr.;Yukinori Koga;Toshio Kawanami;Hiroshi Furuno Dr.;Junji Inanaga Dr.

Angewandte Chemie International Edition 2004 Volume 43(Issue 27) pp:

Publication Date(Web):29 JUN 2004

DOI:10.1002/anie.200454174

Spontaneous trimerization of fluoro(triisopropylsilyl)acetylene, prepared from 1,1-difluoroethylene in one step, gives the corresponding fluorinated Dewar benzene derivative, whose structure was determined by X-ray diffraction (see picture).

Synthesis and Reactions of (2,2,2-Trifluoroethyl)triphenylphosphonium Trifluoromethanesulfonate

Co-reporter:Takeshi Hanamoto;Noriko Morita;Keiko Shindo

European Journal of Organic Chemistry 2003 Volume 2003(Issue 21) pp:

Publication Date(Web):22 OCT 2003

DOI:10.1002/ejoc.200300395

(2,2,2-Trifluoroethyl)triphenylphosphonium trifluoromethanesulfonate (triflate) (1) was readily synthesized in high yield from triphenylphosphane and 2,2,2-trifluoroethyl triflate. The Wittig olefination of 1 with aromatic aldehydes bearing electron-withdrawing groups with CsF as a base in DMF proceeded cleanly, producing the corresponding 3,3,3-trifluoropropenylidene compounds in good yields. On the other hand, the hydrolysis of 1 in methanol containing sodium hydroxide gave (2,2-dimethoxyvinyl)triphenylphosphonium triflate (6a) in high yield instead of the corresponding (2,2,2-trifluoroethyl)diphenylphosphane oxide. Furthermore, reactions between 1 and secondary amines exclusively gave the novel (Z)-(2-amino-2-fluorovinyl)triphenylphosphonium triflates (10) in high yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Synthesis of mono-fluorinated functionalized cyclopropanes and aziridines using the α-fluorovinyl diphenyl sulfonium salt

Co-reporter:Kensuke Hirotaki, Yui Takehiro, Ryo Kamaishi, Yasunori Yamada and Takeshi Hanamoto

Chemical Communications 2013 - vol. 49(Issue 72) pp:NaN7967-7967

Publication Date(Web):2013/07/31

DOI:10.1039/C3CC44519D