論文 - 山田　徹

Lewis Acid-catalyzed Decarboxylative Cyanation of Cyclic Enol Carbonates ®Access to Multi-substituted ¢-Ketonitriles®

Yokoyama H., Dokai Y., Kimaru N., Saito K., Yamada T.

Chemistry Letters （Chemistry Letters）  51 （ 4 ） 469 - 472 2022年04月

共著,  ISSN  03667022

　概要を見る

A Lewis acid-catalyzed decarboxylative substitution reaction of cyclic enol carbonates with a cyanation reagent was developed to give ¢-ketonitriles in good yield. It is proposed that the reaction proceeds through an oxyallyl cation intermediate or its equivalent. Interestingly, cyanation selectively took place at the more hindered site of the intermediate to afford a multi-substituted ¢-ketonitrile. This regioselectivity was observed by the cyanation of a wide range of substrates and is discussed in terms of the reaction mechanism.

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Microwave-specific enhancement of nazarov cyclization

Kubota Y., Kawanori T., Sawada T., Saito K., Yamada T.

Chemistry Letters （Chemistry Letters）  50 （ 1 ） 144 - 146 2021年01月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  03667022

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A copper-catalyzed Nazarov cyclization was carried out under conventional heating conditions and microwave conditions. Under strictly temperature-controlled conditions, the use of microwave irradiation improved the chemical yields. Consequently, the kinetic rate of the microwave irradiation was 5.8 times higher than that of the conventional heating conditions. These observations suggested that the microwave specific effects enhanced the efficiency of the Nazarov reaction.

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

Sadamitsu Y., Saito K., Yamada T.

Chemical Communications （Chemical Communications）  56 （ 66 ） 9517 - 9520 2020年08月

ISSN  13597345

　概要を見る

© The Royal Society of Chemistry. 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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Thermal decarboxylative Nazarov cyclization of cyclic enol carbonates involving chirality transfer

Kozuma A., Komatsuki K., Saito K., Yamada T.

Chemistry Letters （Chemistry Letters）  49 （ 1 ） 60 - 63 2020年

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  03667022

　概要を見る

© 2020 The Chemical Society of Japan. Decarboxylative Nazarov cyclization of chiral cyclic enol carbonates proceeded to afford chiral 2-cyclopentenones with excellent chirality transfer under thermal conditions without any catalyst. Interestingly, the thermal decarboxylative Nazarov cyclization furnished the desired product with better chirality transfer than the Lewis acid-catalyzed reaction.

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Silver-Catalyzed Carbon Dioxide Fixation on Alkynylindenes

Okumura A., Chuang P.Y., Saito K., Yamada T.

Organic Letters （Organic Letters）  2020年

ISSN  15237060

　概要を見る

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

Komatsuki K., Kozuma A., Saito K., Yamada T.

Organic Letters （Organic Letters）  21 （ 17 ） 6628 - 6632 2019年09月

ISSN  15237060

　概要を見る

© 2019 American Chemical Society. 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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Microwave specific effect on catalytic enantioselective reactions

Yamada T.

Asia-Pacific Microwave Conference Proceedings, APMC （Asia-Pacific Microwave Conference Proceedings, APMC）  2018-November   1627 - 1629 2019年01月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  9784902339451

　概要を見る

© 2018 IEICE The microwave specific effect was investigated on the catalytic enantioselective reactions; atropo-enantiveselective ring-opening reaction of biaryl lactones and enantioselective Claisen rearrangement reaction. These reactions were efficiently enhanced with microwave irradiation under reaction temperature control, thought any loss of the enantioselectivities were not detected. It was also found that the racemization rate of the atropo-optically active biaryl lactone was enhanced by microwave irradiation. As these observations could not be explained by the simple thermal effect, microwave specific effect should be considered.

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

Sadamitsu Y., Okumura A., Saito K., Yamada T.

Chemical Communications （Chemical Communications）  55 （ 66 ） 9837 - 9840 2019年

ISSN  13597345

　概要を見る

© 2019 The Royal Society of Chemistry. 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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7 Silver-Catalyzed CO2 Incorporation

Yamada T., Sekine K., Sadamitsu Y., Saito K.

Silver Catalysis in Organic Synthesis （Silver Catalysis in Organic Synthesis）     407 - 438 2018年12月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  9783527342815

Amidation reaction of carboxylic acid with formamide derivative using SO<inf>3</inf>•pyridine

Kawano S., Saito K., Yamada T.

Chemistry Letters （Chemistry Letters）  47 （ 4 ） 584 - 586 2018年

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  03667022

　概要を見る

© 2018 The Chemical Society of Japan. The amidation reaction of carboxylic acid derivatives was developed using sulfur trioxide pyridine complex (SO3•py) as a commercially available and easily handled oxidant. This method could be applied to the reaction of various aromatic and aliphatic carboxylic acids, including optically active ones, with formamide derivatives to afford the corresponding amides in good to high yields.

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Microwave-specific effect on enantioselective reactions

山田 徹

Journal of the Japan Petroleum Institute （石油学会）  61 （ 2 ） 121 - 128 2018年

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  13468804

　概要を見る

© 2018 Office of the Federal Register. All rights reserved. Microwave irradiation is widely applied to organic synthesis. Many advantages of microwave irradiation, including drastic shortening of reaction time, suppression of side reactions, and/or higher chemical yield, have been proposed. Generally, these effects have been understood merely as a simple thermal effect, since microwave irradiation rapidly raises the temperature of the reaction mixture. However, some observed results could not be understood only by the thermal effect. Recently our group reported that several enantioselective reactions were accelerated under microwave irradiation without loss of enantioselectivity. As these extraordinary results could not be explained by the simple thermal effect, the concept of the "microwave-specific effect" should be considered. We describe our recent experimental results to elucidate the microwave-specific effect. Investigations are described on enantioselective ring-opening reactions of biaryl lactone derivatives, racemization of an optically pure biaryl lactone derivative, enantioselective Claisen rearrangement reaction, enantioselective Conia-ene reaction and ring-closing metathesis reaction. These reactions or racemization of optically pure compounds were accelerated under microwave conditions. Such reaction acceleration of enantioselective reactions was observed without loss of enantioselectivity.

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Amidation Reaction of Carboxylic Acid with Formamide Derivative Using SO3·pyridine

山田 徹

Chem. Lett. （日本化学会）  47   584 - 586 2018年

研究論文（学術雑誌）, 共著, 査読有り

Stereospecific Decarboxylative Nazarov Cyclization Mediated by Carbon Dioxide for the Preparation of Highly Substituted 2-Cyclopentenones

山田 徹

Angew. Chem. Int. Ed. （Wiley）  56   11594 - 11598 2017年

研究論文（学術雑誌）, 共著, 査読有り

Microwave Enhancement on Ring-closing Metathesis of Macrocyclic Bisazole

山田 徹

Chem. Lett. 46   274 - 276 2017年

研究論文（学術雑誌）, 共著, 査読有り

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Access to Tetronic Acids via a Silver-Catalyzed CO2 Incorporation Reaction into Conjugated Ynones

山田 徹

Org. Lett. （ACS）  19   3191 - 3194 2017年

研究論文（学術雑誌）, 共著, 査読有り

Silver-catalyzed Three-component Reaction of Propargylic Amines, Carbon Dioxide, and N-Bromosuccinimide for Stereoselective Preparation of (E)-Bromovinyloxazolidinones

山田 徹

Chem. Lett. （日本化学会）  46   1323 - 1326 2017年

研究論文（学術雑誌）, 共著, 査読有り

Silver-Catalyzed Carboxylation,

山田 徹

Chemical Society Reviews 45   4524 - 4532 2016年

査読有り

Microwave Specific Effect on Catalytic Enantioselective Conia-Ene Reaction

山田 徹

Chem. Lett. 45   649 - 651 2016年

査読有り

Microwave Specific Effect on Catalytic atropo-Enantioselective Ring-Opening Reaction of Biaryl Lactones

山田 徹

Bull. Chem. Soc. Jon. 89   833 - 835 2016年

査読有り

Silver-catalyzed Cascade Carboxylation and Cyclization of Trimethyl(2-methylenebut-3-yn-1-yl)silane Derivatives

山田 徹

Org. Lett. 17   5706 - 5709 2015年

査読有り