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Your search keyword '"Ishikura, Minoru"' showing total 70 results
Start Over Author "Ishikura, Minoru" Publisher wiley-blackwell
70 results on '"Ishikura, Minoru"'

1. Concise Total Syntheses of Pyr­ido[4,3- b]carbazole Alkaloids Using Copper-Mediated 6π-Electrocyclization.

Author

Itoh, Tomoki, Abe, Takumi, Choshi, Tominari, Nishiyama, Takashi, Yanada, Reiko, and Ishikura, Minoru

Subjects
ALKALOID synthesis, RING formation (Chemistry), COPPER catalyst selectivity, CARBAZOLE, CHEMICAL synthesis, ORGANIC synthesis
Abstract

Concise syntheses of 9-methoxyellipticine, 3,4-dihydroellipticine (µ-alkaloid D), 1,2,3,4-tetrahydroellipticine, 2-methyl-1,2,3,4-tetrahydroellipticine, olivacine, 3,4-dihydroolivacine, (±)-guatambuine, and (±)-janetine were developed starting from hexatriene intermediates readily obtained by Pd-catalyzed tandem cyclization/cross-coupling reaction of indolylborates. The route enables the facile construction of pyrido[4,3- b]carbazoles by Cu-catalyzed 6π-electrocyclization and subsequent transformation of the pyridocarbazole intermediates into pyrido[4,3- b]carbazole alkaloids. [ABSTRACT FROM AUTHOR]

Published
2016
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2. Copper-Catalyzed Tandem Amide N-Arylation and Regioselective Cyclization of 2-Alkynylbenzamides.

Author

Minami, Hideki, Sueda, Takuya, Okamoto, Noriko, Miwa, Yoshihisa, Ishikura, Minoru, and Yanada, Reiko

Subjects
AMIDE derivatives, ARYLATION, COPPER catalysts, BENZAMIDE, REGIOSELECTIVITY (Chemistry), RING formation (Chemistry), PYRIDINE derivatives, NUCLEOPHILIC reactions
Abstract

A new approach to form iminoisocoumarins from readily available and stable 2-alkynylbenzamides was developed by using a tandem copper-catalyzed N-arylation and regioselective 6- endo- dig cyclization in the presence of diaryliodonium salts, a copper catalyst, and 2,6-di- tert-butylpyridine. The arylation occurred at the nitrogen atom rather than the oxygen atom of the amide group, the alkynyl carbon, or the benzene ring of the benzamide. Cyclization occurred through a preferential nucleophilic attack by the oxygen rather than the nitrogen atom of the amide group to produce iminoisocoumarin derivatives in good to moderate yields. [ABSTRACT FROM AUTHOR]

Published
2016
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3. Enantioselective Total Synthesis of 1,3-Disubstituted β-Carboline Alkaloids, (-)-Dichotomine A and (+)-Dichotomide II.

Author

Tagawa, Shinji, Choshi, Tominari, Okamoto, Asuka, Nishiyama, Takashi, Watanabe, Shiroh, Hatae, Noriyuki, Ishikura, Minoru, and Hibino, Satoshi

Abstract

( S)-(-)-Dichotomine A and its enantiomer were synthesized from the key intermediate, methyl 1-(1-hydroxyethyl)-β-carboline-3-carboxylate, by enantioselective esterification with Lipase QLM. The first total synthesis of (+)-dichotomide II and its enantiomer were also achieved from ( S)-(-)-dichotomine A methyl ester and its enantiomer. The absolute configuration of the stereogenic center of the reported (+)-dichotomide II was determined to be R. [ABSTRACT FROM AUTHOR]

Published
2013
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4. Total Synthesis of Calothrixins A and B by Palladium-Catalyzed Tandem Cyclization/Cross-Coupling Reaction of Indolylborate.

Author

Abe, Takumi, Ikeda, Toshiaki, Choshi, Tominari, Hibino, Satoshi, Hatae, Noriyuki, Toyata, Eiko, Yanada, Reiko, and Ishikura, Minoru

Abstract

The palladium-catalyzed tandem cyclization/cross-coupling reaction of triethyl(indol-2-yl)borate with vinyl bromide was successfully used in the concise total synthesis of the indolophenanthridine alkaloids, calothrixins A and B. [ABSTRACT FROM AUTHOR]

Published
2012
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14. ChemInform Abstract: One-Pot Access to 3,3′-Bisindolylmethanes Through the Intermolecular Pummerer Reaction.

Author

Ishikura, Minoru, Abe, Takumi, Ikeda, Toshiaki, Itoh, Tomoki, Hatae, Noriyuki, and Toyota, Eiko

Subjects
*CHEMICAL equations, *PUMMERER rearrangement, *METHANE derivatives
Abstract

The article presents chemical equations related to the article "One-Pot Access to 3,3'-Bisindolylmethanes through the Intermolecular Pummerer Reaction" by M. Ishikura and others published in the periodical "Heterocycles" in 2014.

Published
2014
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