Reviews, Commentaries, etc. - Yamada, Toru

Lewis Acid‐Mediated Decarboxylative Allylation of Enol Carbonates

Yoichi Dokai and Takuma Nishizawa and Kodai Saito and Tohru Yamada

Helvetica Chimica Acta (Wiley)  104 ( 7 )  2021.07

Rapid communication, short report, research note, etc. (scientific journal), Joint Work,  ISSN  0018019X

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A homoallylic ketone can be transformed and functionalized by various synthetic reactions, and thus, is regarded as one of the representative building blocks in organic chemistry. An additional route to access homoallylic ketones, namely, a Lewis acid-mediated decarboxylative allylation of cyclic enol carbonates, prepared by fixation of carbon dioxide onto propargyl alcohols, was developed in this work. The treatment of a cyclic enol carbonate with a Lewis acid in the presence of an allylsilane resulted in the formation of a homoallylic ketone. It was found that the title reaction proceeded well by the combined use of zirconium tetrachloride with allyltrimethylsilane. The allylation occurred with high regioselectivity and the corresponding homoallylic ketones were obtained in good-to-high yields. A reaction mechanism involving the decarboxylative formation of an oxyallyl cation equivalent is proposed.

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Decarboxylation-triggered homo-Nazarov cyclization of cyclic enol carbonates catalyzed by rhenium complex

Natsuki Kimaru and Keiichi Komatsuki and Kodai Saito and Tohru Yamada

Chemical Communications (Royal Society of Chemistry ({RSC}))  57 ( 50 ) 6133 - 6136 2021

Rapid communication, short report, research note, etc. (scientific journal),  ISSN  13597345

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Decarboxylative homo-Nazarov cyclization catalyzed by a Lewis acid was achieved using a cyclic enol carbonate bearing a cyclopropane moiety as a substrate. Various substrates were converted into the corresponding multi-substituted cyclohexenones in good yieldsviadecarboxylation, followed by 6-membered ring formation involving cyclopropane-ring-opening.

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Silver-Catalyzed Carbon Dioxide Fixation on Alkynylindenes

Akira Okumura and Po-Yao Chuang and Kodai Saito and Tohru Yamada

Organic Letters (American Chemical Society ({ACS}))  22 ( 21 ) 8648 - 8651 2020.11

Rapid communication, short report, research note, etc. (scientific journal), Joint Work,  ISSN  15237060

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The synthesis of polycyclic indene derivatives via silver-catalyzed carbon dioxide fixation on 2-alkynylindene derivatives was achieved by nucleophilic addition of the indenyl anion to carbon dioxide involving carbon-carbon bond formation and subsequent intramolecular cyclization to the alkyne part activated by a silver catalyst. This cascade process could be applied to various substrates to obtain the corresponding products in high yields. The endo/exo selectivity of the cyclization could be controlled by the steric or electronic effect of the substituents on the substrates, and 6-endo-selective cyclization was realized to afford α-pyrone-fused indenes.

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Stereoselective amination via vinyl-silver intermediates derived from silver-catalyzed carboxylative cyclization of propargylamine

Yuta Sadamitsu and Kodai Saito and Tohru Yamada

Chemical Communications (Royal Society of Chemistry ({RSC}))  56 ( 66 ) 9517 - 9520 2020

Rapid communication, short report, research note, etc. (scientific journal),  ISSN  13597345

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The stereoselective synthesis of aminovinyloxazolidinones based on the electrophilic amination of a vinyl-silver intermediate, generated by silver-catalyzed carbon dioxide incorporation on a propargyl amine, was achieved. The geometry of the aminated product was determined by a single crystal X-ray analysis and NOE measurement and it was elucidated that the geometry was proved to be opposite to the geometry predicted from the previous silver-catalyzed carbon dioxide fixation on a propargyl amine derivative. This unexpected stereoselectivity could be successfully explained by a radical mechanism. This journal is

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Decarboxylative Nazarov Cyclization-Based Chirality Transfer for Asymmetric Synthesis of 2-Cyclopentenones

Keiichi Komatsuki and Akane Kozuma and Kodai Saito and Tohru Yamada

Organic Letters (American Chemical Society ({ACS}))  21 ( 17 ) 6628 - 6632 2019.09

Rapid communication, short report, research note, etc. (scientific journal),  ISSN  15237060

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Asymmetric synthesis of 2-cyclopentenones was achieved by chirality transfer based on Lewis acid catalyzed decarboxylative Nazarov cyclization of optically active cyclic enol carbonates, which are prepared by silver-catalyzed carbon dioxide incorporation into optically pure propargyl alcohols. The stereochemistry at the 4,5-positions of the 2-cyclopentenones was cleanly constructed by reflecting the stereochemistry of the starting materials. This method could be applied to various substrates to obtain the corresponding products in high yields with highly efficient chirality transfer.

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Kolbe–Schmitt type reaction under ambient conditions mediated by an organic base

Yuta Sadamitsu and Akira Okumura and Kodai Saito and Tohru Yamada

Chemical Communications (Royal Society of Chemistry ({RSC}))  55 ( 66 ) 9837 - 9840 2019

Rapid communication, short report, research note, etc. (scientific journal),  ISSN  13597345

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The combined use of an organic base for resorcinols realized a Kolbe-Schmitt type reaction under ambient conditions. When resorcinols (3-hydroxyphenol derivatives) were treated with DBU under a carbon dioxide atmosphere, nucleophilic addition to carbon dioxide proceeded to afford the corresponding salicylic acid derivatives in high yields.

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金触媒と光が織りなす反応の世界＝金(I)/金(III)の触媒サイクルを経る反応の新展開

YAMADA TOHRU

化学 (化学同人)  73 ( 2 ) 66 - 67 2018

Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Joint Work,  ISSN  0451-1964

Silver-Catalyzed CO2 Incorporation Reactions

YAMADA TOHRU

TCIMAIL (東京化成工業株式会社)  175   2 - 13 2017

Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Single Work,  ISSN  1349-4848

銀触媒を用いる二酸化炭素の固定化反応

YAMADA TOHRU

TCIメール (東京化成工業株式会社)  175   2 - 18 2017

Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media), Single Work,  ISSN  1349-4856