Takamitsu Hosoya

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Organization: RIKEN Center for Life Science Technologies , Japan
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Title: (PhD)
Co-reporter:Hironobu Sakaguchi, Yuta Uetake, Masato Ohashi, Takashi Niwa, Sensuke Ogoshi, and Takamitsu Hosoya
Journal of the American Chemical Society September 13, 2017 Volume 139(Issue 36) pp:12855-12855
Publication Date(Web):August 29, 2017
DOI:10.1021/jacs.7b08343
Monodefluoroborylation of polyfluoroalkenes has been achieved in a regioselective manner under mild conditions via copper catalysis. The method has shown an extremely broad scope of substrates, including (difluorovinyl)arenes, tetrafluoroethylene (TFE), (trifluorovinyl)arenes, and trifluoromethylated monofluoroalkenes. The choice of boron source was important for the efficient transformation of (difluorovinyl)arenes; (Bpin)2 was suitable for substrates with an electron-deficient aryl group and (Bnep)2 for those with an electron-rich aryl group. Derivatization of the (fluoroalkenyl)boronic acid esters to the corresponding potassium trifluoroborate salts has rendered the products easily isolable, which greatly improved the synthetic practicality of the monodefluoroborylation reaction. Stoichiometric experiments indicate that the fate of the regioselectivity depends on the mode of β-fluorine elimination, which depends on the substrate. Further transformation of the boryl group has allowed facile preparation of fluoroalkene derivatives as exemplified by the synthesis of a fluoroalkene mimic of atorvastatin, which potently inhibited the enzyme activity of HMG-CoA reductase.
Co-reporter:Yuto Sumida, Tomoe Sumida, Daisuke Hashizume, and Takamitsu Hosoya
Organic Letters 2016 Volume 18(Issue 21) pp:5600-5603
Publication Date(Web):October 17, 2016
DOI:10.1021/acs.orglett.6b02831
A facile method for preparing diverse aryne–nickel complexes from readily synthesized ortho-borylaryl triflates is described. Exploratory synthetic applications, including the synthesis of 1,2-difunctionalized arenes, based on the nucleophilic character of the aryne–nickel complexes are also demonstrated.
Co-reporter:Yuta Uetake, Takashi Niwa, and Takamitsu Hosoya
Organic Letters 2016 Volume 18(Issue 11) pp:2758-2761
Publication Date(Web):May 23, 2016
DOI:10.1021/acs.orglett.6b01250
Rhodium-catalyzed transformation of alkyl aryl sulfides into arylboronic acid pinacol esters via C–S bond cleavage is reported. In combination with transition-metal-catalyzed sulfanyl group-guided regioselective C–H borylation reactions of alkylthioarenes, this method allows the synthesis of a diverse range of multisubstituted arenes.
Co-reporter:Hidenori Ochiai, Takashi Niwa, and Takamitsu Hosoya
Organic Letters 2016 Volume 18(Issue 23) pp:5982-5985
Publication Date(Web):November 11, 2016
DOI:10.1021/acs.orglett.6b02675
A convenient method for the stereoinversion of secondary alcohols, applicable to stereocongested carbocyclic substrates, is reported. A simple three-step procedure, including triflylation of the hydroxy group, nucleophilic oxygenative displacement by the treatment with aqueous N,N-dimethylformamide (DMF), and methanolysis, allowed for efficient stereoinversion of various substrates, including sugar derivatives, in one pot.
Co-reporter:Takashi Niwa; Hidenori Ochiai; Yasuyoshi Watanabe
Journal of the American Chemical Society 2015 Volume 137(Issue 45) pp:14313-14318
Publication Date(Web):October 21, 2015
DOI:10.1021/jacs.5b10119
Ni/Cu-catalyzed transformation of fluoroarenes to arylboronic acid pinacol esters via C–F bond cleavage has been achieved. Further versatile derivatization of an arylboronic ester has allowed for the facile two-step conversion of a fluoroarene to diverse functionalized arenes, demonstrating the synthetic utility of the method.
Benzeneacetic acid, 4-(methylthio)-, methyl ester
Naphthalene, 2-(3-methyl-2-butenyl)-
Benzene, 1-(methylthio)-4-(phenylmethoxy)-
Benzoic acid, 4-[(methylamino)carbonyl]-, methyl ester
2-Naphthalenecarbothioic acid, S-ethyl ester
Benzenecarbothioic acid, 4-methoxy-, S-ethyl ester
1,1'-Biphenyl, 2-(methylthio)-
THIOPHENE, 3-[4-(METHYLTHIO)PHENYL]-
CARBAMIC ACID, [4-(METHYLTHIO)PHENYL]-, 1,1-DIMETHYLETHYL ESTER
1,3,2-Dioxaborolane,2-[4-[[(1,1-dimethylethyl)dimethylsilyl]oxy]phenyl]-4,4,5,5-tetramethyl-