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5. Chemical Strategies for the Cleavage of the C(sp3)−F Bonds in Perfluoroalkyl Groups.

Author

Doi, Ryohei and Ogoshi, Sensuke

Subjects
*FLUOROALKYL compounds, *POLLUTANTS, *SCISSION (Chemistry), *LEWIS acids, *HOMOGENEOUS catalysis
Abstract

Perfluoroalkyl substances (PFAS) have been recognized as environmental pollutants. Hence, their efficient and mild destruction is a significant research interest. While many research articles and review papers have reported the cleavage of the C(sp2)−F bonds, single C(sp3)−F bond, and CF3 groups in PFAS, in this study, limited and emerging examples of a longer perfluoroalkyl group containing at least one repeating unit of 1,1,2,2‐tetrafluoroethylene was focused. In this Concept, we summarized recent progress on the chemical defluorination of PFAS via the cleavage of unactivated C(sp3)−F bonds in longer perfluoroalkyl groups under mild conditions (~150 °C). In addition to classical reductive defluorination, strategies featuring Lewis acid activation and the transient generation of an unsaturated bond were described. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Synthesis of 2,3-Disubstituted Indoles by Nickel(0)-Catalyzed Migratory Cycloisomerization of o-Alkynylanilides

Author

Koshiba, Mikiko, Furuki, Yuto, Morisaki, Kazuhiro, Doi, Ryohei, Sato, Yoshihiro, Koshiba, Mikiko, Furuki, Yuto, Morisaki, Kazuhiro, Doi, Ryohei, and Sato, Yoshihiro

Abstract

We herein report a nickel-catalyzed migratory cycloisomerization of o-alkynylanilides, giving 2,3-disubstituted indoles in good yields. The cyclization proceeded via acyl transfer on the nitrogen atom of the substrate to C3-position in the product, and an N-heterocyclic carbene (NHC) ligand such as ICy or SICy was found to be suitable in this reaction. It was thought that the reaction proceeds via an aza-nickelcyclepentene intermediate formed from alkyne and the C=O bond of the amide moiety in o-alkynylanilides.

Published
2023

16. Transformation of Tetrafluoroethylene Using Transition-Metal Complexes.

Author

Doi, Ryohei, Zhou, Yuyang, and Ogoshi, Sensuke

Subjects
*TETRAFLUOROETHYLENE, *ORGANOFLUORINE compounds, *PLATINUM group, *FLUOROPOLYMERS, *RUTHENIUM compounds, *PALLADIUM compounds, *COUPLING reactions (Chemistry), *SONOGASHIRA reaction
Abstract

Tetrafluoroethylene (TFE) is an industrial organofluorine feedstock that is used predominantly to fabricate fluorinated polymers. TFE exhibits excellent potential as a building block for synthesizing organofluorine compounds, which are increasingly gaining attention as functional materials, pharmaceuticals, and agrochemicals. In particular, the use of transition-metal complexes in the transformation of TFE is of great interest, considering their widespread use in syntheses of organofluorine compounds over the last few decades. This review highlights studies on the transformation of TFE into organofluorine compounds using transition-metal complexes, except for polymerizations. Our review covers cross-coupling reactions via C–F bond cleavage, fluoroalkylation reactions, multicomponent couplings, and olefin metathesis. 1 Introduction 2 Palladium Complexes 3 Copper Complexes 4 Nickel Complexes 5 Ruthenium Complexes 6 Rhodium Complexes 7 Summary and Perspective [ABSTRACT FROM AUTHOR]

Published
2023
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17. Design, synthesis, and structural characterization of helix-forming aliphatic homo-δ-peptides based on conformational restriction due to the structural characteristics of cyclopropane

Author

Watanabe, Mizuki, primary, Nagata, Makoto, additional, Doi, Ryohei, additional, Uemura, Mai, additional, Ochiai, Nanase, additional, Ichinose, Wataru, additional, Fujiwara, Koichi, additional, Kameda, Tomoshi, additional, Sato, Yoshihiro, additional, Takeuchi, Koh, additional, and Shuto, Satoshi, additional

Published
2021
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18. Nickel-Catalyzed -Carboxylation of Ynamides with Carbon Dioxide

Author

Doi, Ryohei, Okano, Taichi, Abdullah, Iman, and Sato, Yoshihiro

Subjects
hydrocarboxylation, ynamides, carbon dioxide, β-amino acids, nickel catalysis
Abstract

A nickel-catalyzed -selective hydrocarboxylation of ynamides to give protected dehydro--amino acids was developed. The key to exclusive -selectivity was the use of diethylzinc as a reductant in the presence of a magnesium salt. The reaction was conducted with bis(acetylacetonato)nickel(II) instead of costly and sensitive bis(1,5-cyclooctadiene)nickel(0). In addition, the optimized ligand was inexpensive 1,5-cyclooctadiene. Investigation of the substrate scope revealed that both nitrogen and alkyne substituents have marked effects on the reaction efficiency. We obtained experimental clues that indicated the formation of a vinylzinc intermediate that forms a C-C bond with CO (2) .

Published
2019

19. Palladium-Catalyzed Decarboxylative Alkynylation of alpha-Acyloxyketones by C(sp(3))-O Bond Cleavage

Author

Doi, Ryohei, Yabuta, Akimasa, and Sato, Yoshihiro

Subjects
alkynylation, ketones, decarboxylation, palladium, enolates
Abstract

Palladium-catalyzed decarboxylative alkynylation of alpha-acyloxyketones triggered by C(sp(3))-O bond cleavage is disclosed. The decarboxylation strategy featuring a neutral reaction condition enabled an unprecedent catalytic alkynylation of a ketone enolate. The reaction was applied to a variety of substrates, giving desired products in good yields. We successfully obtained X-ray crystallography of a new palladium-enolate intermediate that was synthesized by a reaction of [Pd(cod)(CH2TMS)(2)] with XPhos and alpha-acyloxyketone at room temperature, indicating facile C(sp(3))-O bond disconnection.

Published
2019

29. Palladium‐Catalyzed Decarboxylative Alkynylation of α‐Acyloxyketones by C(sp3)−O Bond Cleavage.

Author

Doi, Ryohei, Yabuta, Akimasa, and Sato, Yoshihiro

Subjects
*SCISSION (Chemistry), *X-ray crystallography, *DECARBOXYLATION, *KETONES
Abstract

Palladium‐catalyzed decarboxylative alkynylation of α‐acyloxyketones triggered by C(sp3)−O bond cleavage is disclosed. The decarboxylation strategy featuring a neutral reaction condition enabled an unprecedent catalytic alkynylation of a ketone enolate. The reaction was applied to a variety of substrates, giving desired products in good yields. We successfully obtained X‐ray crystallography of a new palladium–enolate intermediate that was synthesized by a reaction of [Pd(cod)(CH2TMS)2] with XPhos and α‐acyloxyketone at room temperature, indicating facile C(sp3)−O bond disconnection. [ABSTRACT FROM AUTHOR]

Published
2019
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30. Nickel-catalyzed hydrocarboxylation of ynamides with CO2 and H2O : observation of unexpected regioselectivity

Author

Doi, Ryohei, Abdullah, Iman, Taniguchi, Takahisa, Saito, Nozomi, Sato, Yoshihiro, Doi, Ryohei, Abdullah, Iman, Taniguchi, Takahisa, Saito, Nozomi, and Sato, Yoshihiro

Abstract

We describe the nickel-catalyzed hydrocarboxylation of ynamides with CO2 and H2O to afford a variety of alpha-amino-alpha, beta-unsaturated esters with high regioselectivities. The selective alpha-carboxylation of ynamides with this catalytic protocol is unexpected in view of the electronic bias of ynamides and is in sharp contrast to our previous study in which a stoichiometric amount of Ni(0) was used to form a beta-carboxylated product exclusively. We revealed that this unexpected C-C bond formation was induced by the combination of Zn and MgBr2.

Published
2017

36. Nickel Nanoparticle-catalyzed Carboxylation of Unsaturated Hydrocarbon with CO2Using Sulfur-modified Au-supported Nickel Material

Author

Taniguchi, Takahisa, Saito, Nozomi, Doi, Ryohei, Kimoto, Arato, Hoshiya, Naoyuki, Fujiki, Katsumasa, Shuto, Satoshi, Fujioka, Hiromichi, Arisawa, Mitsuhiro, and Sato, Yoshihiro

Abstract

A hydrocarboxylation reaction of alkyne or styrene derivatives with CO2proceeded smoothly by using an air-stable nano-sized nickel catalyst supported on sulfur-modified gold (SANi), giving functionalized acrylic acids and phenylpropionic acids including an anti-inflammatory drug, Flurbiprofen. Notably, SANi could be recycled several times without a significant decrease of the yield.A hydrocarboxylation reaction of alkyne or styrene derivatives with CO2proceeded smoothly by using an air-stable nano-sized nickel catalyst supported on sulfur-modified gold (SANi), giving functionalized acrylic acids and phenylpropionic acids including an anti-inflammatory drug, Flurbiprofen. Notably, SANi could be recycled several times without a significant decrease of the yield.

Published
2019
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40. Nickel-catalyzed hydrocarboxylation of ynamides with CO2 and H2O: observation of unexpected regioselectivity.

Author

Doi, Ryohei, Abdullah, Iman, Taniguchi, Takahisa, Saito, Nozomi, and Sato, Yoshihiro

Subjects
*YNAMIDES, *CARBOXYLATION, *NICKEL, *ALKYNES, *TRANSITION metals
Abstract

We describe the nickel-catalyzed hydrocarboxylation of ynamides with CO2 and H2O to afford a variety of α-amino-α,β-unsaturated esters with high regioselectivities. The selective α-carboxylation of ynamides with this catalytic protocol is unexpected in view of the electronic bias of ynamides and is in sharp contrast to our previous study in which a stoichiometric amount of Ni(0) was used to form a β-carboxylated product exclusively. We revealed that this unexpected C–C bond formation was induced by the combination of Zn and MgBr2. [ABSTRACT FROM AUTHOR]

Published
2017
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46. Copper-Catalyzed Reaction of Trifluoromethylketones with Aldehydes via a Copper Difluoroenolate.

Author

Doi, Ryohei, Ohashi, Masato, and Ogoshi, Sensuke

Subjects
*COPPER, *ALDEHYDES, *TRANSITION metals, *CARBENES, *ALKOXIDES
Abstract

A copper-catalyzed reaction of easily accessible a,a,a-trifluoromethylketones with various aldehydes affords difluoro-methylene compounds in the presence of diboron and NaOtBu. The key process of the reaction is the formation of a copper difluoroenolate by 1,2-addition of a borylcopper intermediate to α,α,α-trifluoromethylketones and subsequent b-fluoride elimination. Mechanistic studies including the isolation and characterization of a possible anionic copper alkoxide intermediate are also described. [ABSTRACT FROM AUTHOR]

Published
2016
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48. Regioselective C-F Bond Transformations of Silyl Difluoroenolates

Author

Doi, Ryohei, Kajiwara, Koki, Negoro, Taiki, Koh, Kenta, Ogoshi, Sensuke, Doi, Ryohei, Kajiwara, Koki, Negoro, Taiki, Koh, Kenta, and Ogoshi, Sensuke

Abstract

Doi R., Kajiwara K., Negoro T., et al. Regioselective C-F Bond Transformations of Silyl Difluoroenolates. Organic Letters 25, 5542 (2023); https://doi.org/10.1021/acs.orglett.3c02057., Herein, we report the development of a nickel-catalyzed cross-coupling reaction of silyl difluoroenolates with aryl zinc reagents via C-F bond cleavage. Treatment of a stoichiometric amount of Ni(0)/N-heterocyclic carbene (NHC) with silyl difluoroenolates in the presence of a lithium salt resulted in C-F bond cleavage to selectively afford the corresponding (Z)-alkenyl Ni complexes. On the basis of the observations, we developed a catalytic cross-coupling reaction that selectively delivers a single geometric isomer of a fluoroenolate.

49. Difluoromethylene insertion into fluoroalkyl copper complexes

Author

Zhou, Yuyang, Doi, Ryohei, Ogoshi, Sensuke, Zhou, Yuyang, Doi, Ryohei, and Ogoshi, Sensuke

Abstract

Zhou Y., Doi R., Ogoshi S.. Difluoromethylene insertion into fluoroalkyl copper complexes. Chemical Communications 59, 11504 (2023); https://doi.org/10.1039/d3cc03481j., Herein, we report the insertion of a difluoromethylene into 1,1,2,2-tetrafluoro-2-arylethyl copper complexes to synthesize extended perfluoroalkyl-bridged compounds that have various functional groups on each edge (ArCF2CF2(CF2)nR, R = arenes, halogens, alkyl, alkenyl, and benzyloxycarbonyl). Further, the one-pot syntheses of perfluoroalkyl-bridged compounds from aryl boronic acid esters were carried out.

50. Difluoromethylene insertion into fluoroalkyl copper complexes

Author

Zhou, Yuyang, Doi, Ryohei, Ogoshi, Sensuke, Zhou, Yuyang, Doi, Ryohei, and Ogoshi, Sensuke

Abstract

Zhou Y., Doi R., Ogoshi S.. Difluoromethylene insertion into fluoroalkyl copper complexes. Chemical Communications 59, 11504 (2023); https://doi.org/10.1039/d3cc03481j., Herein, we report the insertion of a difluoromethylene into 1,1,2,2-tetrafluoro-2-arylethyl copper complexes to synthesize extended perfluoroalkyl-bridged compounds that have various functional groups on each edge (ArCF2CF2(CF2)nR, R = arenes, halogens, alkyl, alkenyl, and benzyloxycarbonyl). Further, the one-pot syntheses of perfluoroalkyl-bridged compounds from aryl boronic acid esters were carried out.

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