論文 - ウヤヌク　ムハメット

Electrochemical oxidative dearomatization of electron-deficient phenols using Br<SUP>+</SUP>/Br<SUP>-</SUP> catalysis 査読有り

Matsui, K; Uyanik, M; Ishihara, K

CHEMICAL COMMUNICATIONS   61 巻 ( 10 ) 頁： 2075 - 2078   2025年1月

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Communications  

An electrochemical method for the oxidative dearomatization of electron-deficient phenols by employing tetrabutylammonium bromide as a mediator under aqueous biphasic conditions is reported. This approach represents a safer alternative to the use of stoichiometric chemical oxidants and enables oxidative dearomative spirolactonization and spiroetherification reactions. Compared to previous approaches based on direct electrolysis, this strategy expands the substrate scope to electron-deficient phenols. Cyclic-voltammetry analysis suggests that the bromide ions might be oxidized to Br2 or Br3− ions that are in equilibrium with the catalytically active hypobromite under aqueous conditions.

DOI： 10.1039/d4cc06472k

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PubMed

その他リンク： https://pubs.rsc.org/en/content/articlelanding/2025/cc/d4cc06472k

Unraveling Alcohol Additive Effects on Hypervalent Iodine(III)-Catalyzed Asymmetric Phenolic Dearomatization: Ligand Substitution and Low-Barrier Hydrogen Bonds 査読有り 国際共著

Zheng, HL; Cai, L; Lai, XY; Uyanik, M; Ishihara, K; Xue, XS

ACS CATALYSIS   15 巻 ( 1 ) 頁： 370 - 380   2024年12月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Catalysis  

Despite the widespread use of hexafluoropropanol (HFIP) as a “magic” solvent or additive in organic synthesis, its fundamental mechanisms lag far behind. This study presents mechanistic insights into the puzzling alcohol additive effects observed in Ishihara’s conformationally flexible C2-symmetric iodoarene-catalyzed asymmetric phenolic dearomatization through density functional theory calculations. The results reveal that due to the “booster effect” of fluorinated alcohols, HFIP assembles a trimeric hydrogen bond cluster that displaces a ligand from the active iodine(III) catalyst and forms a low-barrier hydrogen bond with the substrate, which significantly enhances the oxidizing power of the iodine(III) center, thus facilitating the dearomatization of electron-deficient phenols. Conversely, methanol is found to promote the dearomatization of electron-rich phenols via a formally similar yet distinct mechanism, thus highlighting the unique role of HFIP as an additive. The insights gained from this investigation advance our molecular-level understanding of the synergistic interactions between catalysts and additives, potentially guiding the design of catalytic systems that exploit these effects for broader applications.

DOI： 10.1021/acscatal.4c06557

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その他リンク： https://pubs.acs.org/doi/10.1021/acscatal.4c06557

Inner-Bond-Cleavage Approach to Figure-Eight Macrocycles from Planar Aromatic Hydrocarbons 査読有り 国際共著 国際誌 Open Access

Yoshina, R; Hirano, J; Nishimoto, E; Sakamoto, Y; Tajima, K; Minabe, S; Uyanik, M; Ishihara, K; Ikai, T; Yashima, E; Omine, T; Ishiwari, F; Saeki, A; Kim, J; Oh, J; Kim, D; Liu, GT; Yasuda, T; Shinokubo, H; Fukui, N

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   146 巻 ( 43 ) 頁： 29383 - 29390   2024年9月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the American Chemical Society  

Figure-eight-shaped nonplanar π-systems adopt distinctive chiral D2-symmetric structures, which are ideal for realizing efficient circularly polarized luminescence (CPL). However, the short-step and enantioselective synthesis of figure-eight π-systems represents a considerable challenge for the conventional bottom-up synthetic strategy. Herein, we report that the oxidative cleavage of the internal double bond of a commercially available polycyclic aromatic hydrocarbon, i.e., dibenzo[g,p]chrysene (DBC), catalytically affords a figure-eight electron-accepting macrocycle, i.e., cyclobisbiphenylenecarbonyl (CBBC), with high scalability (up to 3.3 g) and excellent enantioselectivity (94% ee). This inner-bond-cleavage approach also applies to larger PAHs, affording highly distorted molecular frameworks that comprise two figure-eight subunits. Furthermore, we demonstrate that the peripheral functionalization of CBBC with carbazole afforded donor-acceptor-type emitter, which shows thermally activated delayed fluorescence and emits CPL with a g value of 1.0 × 10-2. This g value is ten times higher than those of previously reported chiral TADF-active emitters for circularly polarized organic light-emitting diodes. These results demonstrate that oxidative inner-bond cleavage is a powerful synthetic strategy for creating innovative materials that incorporate molecules with figure-eight structures.

DOI： 10.1021/jacs.4c07985

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その他リンク： https://pubs.acs.org/doi/10.1021/jacs.4c07985

Oxidative Dearomative Coupling of Electron-Deficient Arenols Using Hypohalite Catalysis 査読有り

Kato, T; Sahara, N; Akagawa, S; Uyanik, M; Ishihara, K

ORGANIC LETTERS   26 巻 ( 34 ) 頁： 7255 - 7260   2024年8月

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Organic Letters  

We developed performant in situ hypohalite, especially hypobromite, catalysis for the oxidative dearomatization of low-reactivity electron-deficient arenols. The reaction scope encompasses inter- and intramolecular oxidative dearomative C-O, C-N, and C-C coupling reactions. Notably, using a chiral ammonium countercation, we achieved enantioselective hypobromite catalysis for oxidative dearomative coupling reactions. Mechanistic studies revealed that the reaction mechanisms might differ depending on the halide identity.

DOI： 10.1021/acs.orglett.4c02787

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Hypoiodite-Catalyzed Oxidative α-C-N Coupling of Ketones with Imides and Azoles 招待有り 査読有り 国際誌

Tsukahara, M; Uyanik, M; Ishihara, K

ADVANCED SYNTHESIS & CATALYSIS   365 巻 ( 16 ) 頁： 2724 - 2729   2023年8月

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Advanced Synthesis and Catalysis  

Herein, we report a direct method for the synthesis of α-imidoketones and α-azolylketones via hypoiodite-catalyzed oxidative α-C−N coupling of ketones with the corresponding imides and azoles, respectively. The use of inorganic base additives such as cesium carbonate in the presence of 18-crown-6 as a phase transfer catalyst was crucial to induce high reactivity. Control experiments revealed that the basic additives might not only facilitate high-turnover hypoiodite catalysis, but also be involved in the activation of coupling partners.

DOI： 10.1002/adsc.202300716

DOI： 10.1002/adsc.202300716

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その他リンク： https://advanced.onlinelibrary.wiley.com/doi/10.1002/adsc.202300716

1,3-Migrative Ring Expansion of Spiroindolenines to Azepino[3,4-<i>b</i>]indoles 査読有り

Tanaka, H; Yasui, T; Uyanik, M; Ishihara, K

ORGANIC LETTERS   25 巻 ( 14 ) 頁： 2377 - 2381   2023年4月

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Organic Letters  

We serendipitously found an unprecedented 5-to-7-membered ring expansion of 2-alkylspiroindolenines to azepinoindoles mediated by n-tetrabutylammonium fluoride. The starting materials can be easily prepared by the hypoiodite-catalyzed oxidative dearomative spirocyclization of indole derivatives. Mildly basic conditions and electron-deficient protecting groups for the amines were found to be crucial to promoting chemoselective reactions. Moreover, the ring expansion of aniline-derived spiroindolenines proceeds smoothly under much milder conditions using only a catalytic amount of cesium carbonate.

DOI： 10.1021/acs.orglett.3c00207

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その他リンク： https://pubs.acs.org/doi/full/10.1021/acs.orglett.3c00207

Catalyst-Substrate Helical Character Matching Determines the Enantioselectivity in the Ishihara-Type Iodoarenes Catalyzed Asymmetric Kita-Dearomative Spirolactonization 査読有り 国際共著

Zheng H., Cai L., Pan M., Uyanik M., Ishihara K., Xue X.S.

Journal of the American Chemical Society   145 巻 ( 13 ) 頁： 7301 - 7312   2023年4月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the American Chemical Society  

Catalyst design has traditionally focused on rigid structural elements to prevent conformational flexibility. Ishihara’s elegant design of conformationally flexible C2-symmetric iodoarenes, a new class of privileged organocatalysts, for the catalytic asymmetric dearomatization (CADA) of naphthols is a notable exception. Despite the widespread use of the Ishihara catalysts for CADAs, the reaction mechanism remains the subject of debate, and the mode of asymmetric induction has not been well established. Here, we report an in-depth computational investigation of three possible mechanisms in the literature. Our results, however, reveal that this reaction is best rationalized by a fourth mechanism called “proton-transfer-coupled-dearomatization (PTCD)”, which is predicted to be strongly favored over other competing pathways. The PTCD mechanism is consistent with a control experiment and further validated by applying it to rationalize the enantioselectivities. Oxidation of the flexible I(I) catalyst to catalytic active I(III) species induces a defined C2-symmetric helical chiral environment with a delicate balance between flexibility and rigidity. A match/mismatch effect between the active catalyst and the substrate’s helical shape in the dearomatization transition states was observed. The helical shape match allows the active catalyst to adapt its conformation to maximize attractive noncovalent interactions, including I(III)···O halogen bond, N-H···O hydrogen bond, and π···π stacking, to stabilize the favored transition state. A stereochemical model capable of rationalizing the effect of catalyst structural variation on the enantioselectivities is developed. The present study enriches our understanding of how flexible catalysts achieve high stereoinduction and may serve as an inspiration for the future exploration of conformational flexibility for new catalyst designs.

DOI： 10.1021/jacs.2c13295

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キラルアンモニウム次亜ヨウ素酸塩触媒を用いるエナンチオ選択的酸化的脱芳香族化反応 招待有り

ウヤヌク ムハメット, 石原一彰

月間ファインケミカル   51 巻 ( 8 ) 頁： 31 - 39   2022年8月

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担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）  

過酸化水素あるいはアルコール過酸化物の存在下、キラルヨウ化第四級アンモニウムからin situで調製される次亜ヨウ素酸塩を触媒活性種に用いるエナンチオ選択的酸化的環化反応を開発した。本酸化システムの詳細な触媒機構を解明することで、高活性な不斉有機酸化触媒システムの構築に成功し、多くの生物活性物質に含まれる2,3-ジヒドロベンゾフラン、クロマン、テトラヒドロフラン、及びスピロラクトン骨格の新規不斉合成を達成した。

Hypoiodite-Catalyzed Oxidative Umpolung of Indoles forEnantioselective Dearomatization 査読有り Open Access

Tanaka, H; Ukegawa, N; Uyanik, M; Ishihara, K

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   144 巻 ( 13 ) 頁： 5756 - 5761   2022年4月

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the American Chemical Society  

Here we report the oxidative umpolung of 2,3-disubstituted indoles toward enantioselective dearomative aza-spirocyclization to give the corresponding spiroindolenines using chiral quaternary ammonium hypoiodite catalysis. Mechanistic studies revealed the umpolung reactivity of C3 of indoles by iodination of the indole nitrogen atom. Moreover, the introduction of pyrazole as an electron-withdrawing auxiliary group at C2 suppressed a competitive dissociative racemic pathway, and enantioselective spirocyclization proceeded to give not only spiropyrrolidines but also four-membered spiroazetidines that are otherwise difficult to access.

DOI： 10.1021/jacs.2c01852

DOI： 10.1021/jacs.2c01852

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その他リンク： https://pubs.acs.org/doi/10.1021/jacs.2c01852

Hypoiodite-catalysed oxidative homocoupling of arenols and tandem oxidation/cross-coupling of hydroquinones with arenes 査読有り

Muhammet Uyanik, Dai Nagata, Kazuaki Ishihara

Chemical Communications   57 巻 ( 88 ) 頁： 11625 - 11628   2021年10月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/D1CC05171G

DOI： 10.1039/D1CC05171G

Oxidative Ritter-type Chloroamidation of Alkenes Using NaCl and Oxone 招待有り 査読有り

Takehiro Kato, Yuya Okada, Yuto Fujii, Muhammet Uyanik, Kazuaki Ishihara

Asian Journal of Organic Chemistry   10 巻 ( 11 ) 頁： 2907 - 2910   2021年9月

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

A practical and environmentally benign method for the oxidative Ritter-type chloroamidation of alkenes was developed using sodium chloride and oxone as a chlorinating source and an oxidant, respectively. The reaction proceeded smoothly under non-aqueous conditions without the use of any catalyst. Excellent chemoselectivity (i. e., chloroamidation versus dichlorination) could be achieved for electron-deficient styrenes. In addition, this protocol could be easily applied to 7-gram-scale synthesis.

DOI： 10.1002/ajoc.202100575

Chiral Organoiodine-catalyzed Enantioselective Oxidative Dearomatization of Phenols 招待有り 査読有り Open Access

Uyanik, M; Ishizaki, S; Ishihara, K

ORGANIC SYNTHESES   98 巻   頁： 28 - +   2021年

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Organic Syntheses  

DOI： 10.15227/orgsyn.098.0028

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Synthesis of Chiral Organoiodine Catalyst for Enantioselective Oxidative Dearomatization Reactions: <i>N,N</i>′-(2<i>S</i>,2′<i>S</i>)-(2-Iodo-1,3-phenylene)bis(oxy)bis(propane-2,1-diyl)bis(2,4,6-trimethylbenzamide) 招待有り 査読有り Open Access

Uyanik, M; Ishizaki, S; Ishihara, K

ORGANIC SYNTHESES   98 巻   頁： 1 - +   2021年

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Organic Syntheses  

DOI： 10.15227/orgsyn.098.0001

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高活性次亜ヨウ素酸塩/過酸化水素触媒システムを用いるカルボニルの酸化的α-アジド化反応

  23 巻   頁： 10 - 13   2020年12月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

I+/TBHP Catalysis For Tandem Oxidative Cyclization To Indolo[2,3-b]quinolines 招待有り 査読有り

Muhammet Uyanik, Hiroki Tanaka, Kazuaki Ishihara

Asian Journal of Organic Chemistry   10 巻 ( 1 ) 頁： 164 - 169   2020年11月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

A chemoselective I+/TBHP catalysis was developed for tandem oxidative cyclization/aromatization of indole derivatives under nearly neutral conditions to give the corresponding indolo[2,3-b]quinoline sulfonate salts, which could be easily isolated via only simple filtration of the crude reaction mixture. Interestingly both ionic and radical active species would be generated in situ for the corresponding oxidative transformations to proceed in a chemoselective manner.

DOI： 10.1002/ajoc.202000570

Hypoiodite-Catalyzed Chemoselective Tandem Oxidation of Homotryptamines to Peroxy- and Epoxytetrahydropyridoindolenines 査読有り

Muhammet Uyanik, Hiroki Tanaka, Kazuaki Ishihara

Organic Letters   22 巻 ( 20 ) 頁： 8049 - 8054   2020年9月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

We developed the hypoiodite-catalyzed tandem dearomative peroxycyclization of homotryptamine derivatives to peroxytetrahydropyridoindolenines under mild conditions. During the course of a mechanistic study, we found that a tandem oxidative cyclization/epoxidation as an unexpected reaction proceeded in the presence of TEMPO as an additive. Intramolecular oxidative aminocyclization of homotryptamines at the C-2 position would give tetrahydropyridoindole, a common intermediate for both reactions. Control experiments suggested that while oxidative coupling with TBHP at the C-3 position might afford peroxyindolenines, a preferential electrophilic addition of TEMPO+, which might be generated in situ by the hypoiodite-catalyzed oxidation of TEMPO, at C-3 position followed by elimination and epoxidation might give epoxyindolenines. This serendipitous finding prompted us to develop a chemoselective divergent synthesis of peroxy- and epoxyindolenines by simple modification of the reaction conditions.

DOI： 10.1021/acs.orglett.0c03001

Chemo‐ and Enantioselective Oxidative α-Azidation of Carbonyl Compounds 査読有り

Muhammet Uyanik, Naoto Sahara, Mayuko Tsukahara, Yuhei Hattori, Kazuaki Ishihara

Angewandte Chemie International Edition   59 巻 ( 39 ) 頁： 17110 - 17117   2020年6月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

We report high-performance I+/H2O2 catalysis for the oxidative or decarboxylative oxidative α-azidation of carbonyl compounds by using sodium azide under biphasic neutral phase-transfer conditions. To induce higher reactivity especially for the α-azidation of 1,3-dicarbonyl compounds, we designed a structurally compact isoindoline-derived quaternary ammonium iodide catalyst bearing electron-withdrawing groups. The nonproductive decomposition pathways of I+/H2O2 catalysis could be suppressed by the use of a catalytic amount of a radical-trapping agent. This oxidative coupling tolerates a variety of functional groups and could be readily applied to the late-stage α-azidation of structurally diverse complex molecules. Moreover, we achieved the enantioselective α-azidation of 1,3-dicarbonyl compounds as the first successful example of enantioselective intermolecular oxidative coupling with a chiral hypoiodite catalyst.

DOI： 10.1002/anie.202007552

Chemoselective oxidative generation of ortho-quinone methides and tandem transformations 査読有り

Muhammet Uyanik, Kohei Nishioka, Ryutaro Kondo, Kazuaki Ishihara

Nature Chemistry   12 巻 ( 4 ) 頁： 353 - 362   2020年3月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

ortho-Quinone methides are useful transient synthetic intermediates in organic synthesis. These species are most often generated in situ by the acid- or base-mediated transformation of phenols that have been pre-functionalized at a benzylic position, or by biomimetic oxidation of the corresponding ortho-alkylphenols with metal oxidants or transition-metal complexes. Here we describe a method for the transition-metal-free oxidative generation of o-QMs from ortho-alkylarenols, using hypoiodite catalysis under nearly neutral conditions, which can then be applied in one-pot tandem reactions. This method for the chemoselective oxidative generation of ortho-quinone methides may prove superior to previous methods with respect to environmental issues and scope, and can be applied to various tandem reactions such as inter- or intramolecular [4 + 2] cycloaddition, oxa-6π-electrocyclization, conjugate addition and spiroepoxidation.

DOI： 10.1038/s41557-020-0433-4

Chemoselective Oxidative Spiroetherification and Spiroamination of Arenols Using I+/Oxone Catalysis 査読有り

Muhammet Uyanik, Naoto Sahara, Outa Katade, Kazuaki Ishihara

Organic Letters   22 巻 ( 2 ) 頁： 560 - 564   2019年12月

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

We developed a chemoselective oxidative dearomative spiroetherification and spiroamination of arenols using I+/oxone catalysis. The intramolecular dearomative C–O and C–N couplings proceeded much more efficiently under slightly acidic conditions to give the corresponding spiro adducts in higher yields compared with previous methods using transition metal or hypervalent iodine catalysts. Control experiments suggested that both hypoiodous acid and iodine might be active species for these reactions.

DOI： 10.1021/acs.orglett.9b04324

Designer C2-symmetric Chiral Diamide-type Organoiodine Catalysts 招待有り

Muhammet Uyanik, Kazuaki Ishihara

TCI Mail   2019 巻 ( 182 ) 頁： 2 - 16   2019年12月

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

As the global issues of environment, energy, and natural resource scarcity increase, the development
of environmentally friendly and efficient catalytic methodologies of organic synthesis is strongly demanded for the sustainable advancement of material civilization. For this purpose, the use of toxic heavy metals and precious transition metals as reactants and/or catalysts should be avoided as much as possible in the synthesis of medicinal and pharmaceutical products. Over the past decades, iodine compounds have been the focus of great attention due to their mild and chemoselective oxidizing properties and their environmentally benign characteristics in contrast to
toxic metal oxidants. Furthermore, the development of chiral hypervalent iodine-catalyzed enantioselective oxidative transformation is one of the most challenging areas in asymmetric organocatalysis. Here, we demonstrate the rational
design of conformationally flexible chiral diamide-type C2-symmetric organoiodine catalysis based on secondary
nonbonding interactions for the enantioselective oxidative dearomatization of arenols. Several research groups
have also reported highly enantioselective oxidative transformations using these conformationally flexible chiral
organoiodine(III) catalysts or reagents. These examples highlight the substantial scope of conformationally flexible designer organoiodine(III) catalysis.