Faculty Profiles - ISHIHARA Kazuaki

Insight into the Mechanism of the Acylation of Alcohols with Acid Anhydrides Catalyzed by Phosphoric Acid Derivatives Open Access

Hiroyuki Hayashi, Shotaro Yasukochi, Tatsuhiro Sakamoto, Manabu Hatano, Kazuaki Ishihara

The Journal of Organic Chemistry Vol. 86 ( 7 ) page： 5197 - 5212 2021.4

Synthesis of chiral organoiodine catalyst for enantioselective oxidative dearomatization reactions: N,N'-(2S,2'S)-(2-iodo-1,3-phenylene)bis(oxy)bis(propane-2,1-diyl)bis(2,4,6-trimethylbenzamide) Invited Reviewed

Muhammet Uyanik, Shinichi Ishizaki and Kazuaki Ishihara

Org. Synth. Vol. 98 page： 1 - 7 2021.2

Reusable Silica‐Supported Ammonium BINSate Catalysts for Enantio‐ and Diastereoselective Friedel–Crafts‐Type Double Aminoalkylation of N ‐Alkylpyrroles with Aldimines Open Access

Manabu Hatano, Xue Zhao, Takuya Mochizuki, Kyogo Maeda, Ken Motokura, Kazuaki Ishihara

Asian Journal of Organic Chemistry Vol. 10 ( 2 ) page： 360 - 365 2021.2

Chemoselective Transesterification of Methyl (Meth)acrylates Catalyzed by Sodium(I) or Magnesium(II) Aryloxides Open Access

Jie Qi Ng, Hiro Arima, Takuya Mochizuki, Kohei Toh, Kai Matsui, Manussada Ratanasak, Jun-Ya Hasegawa, Manabu Hatano, Kazuaki Ishihara

ACS Catalysis Vol. 11 ( 1 ) page： 199 - 207 2021.1

Chiral organoiodine-catalyzed enantioselective oxidative dearomatization of phenols Open Access

Muhammet Uyanik, Shinichi Ishizaki, Kazuaki Ishihara

Organic Syntheses Vol. 98 page： 28 - + 2021

Synthesis of chiral organoiodine catalyst for enantioselective oxidative dearomatization reactions: N,n'-(2s,2's)-(2-iodo-1,3-phenylene)bis(oxy)bis(propane-2,1-diyl)bis(2,4,6-trimethylbenzamide) Open Access

Muhammet Uyanik, Shinichi Ishizaki, Kazuaki Ishihara

Organic Syntheses Vol. 98 page： 1 - + 2021

Enantioselective Aza-Friedel–Crafts Reaction of Indoles and Pyrroles Catalyzed by Chiral C1-Symmetric Bis(phosphoric Acid) Open Access

Manabu Hatano, Kohei Toh, Kazuaki Ishihara

Organic Letters Vol. 22 ( 24 ) page： 9614 - 9620 2020.12

Reusable silica-supported ammonium BINSate catalysts for enantio- and diastereoselective Friedel–Crafts-type double aminoalkylation of N-alkylpyrroles with aldimines Invited Reviewed

Manabu Hatano, Xue Zhao, Takuya Mochizuki, Kyogo Maeda, Ken Motokura, Kazuaki Ishihara

Asian J. Org. Chem. Vol. 10 ( 2 ) page： 360 - 365 2020.12

I+/TBHP catalysis for the tandem oxidative cyclization to indolo[2,3-b]quinolines Invited Reviewed

Muhammet Uyanik, Hiroki Tanaka, Kazuaki Ishihara

Asian J. Org. Chem. Vol. 10 ( 1 ) page： 164 - 169 2020.11

Multifactor Control of Vinyl Monomer Sequence, Molecular Weight, and Tacticity via Iterative Radical Additions and Olefin Metathesis Reactions Open Access

Masato Miyajima, Kotaro Satoh, Takahiro Horibe, Kazuaki Ishihara, Masami Kamigaito

Journal of the American Chemical Society Vol. 142 ( 44 ) page： 18955 - 18962 2020.11

Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society

Monomer sequence control in terms of a single monomer unit, particularly in vinyl polymers, is one of the largest challenges in polymer chemistry. Furthermore, multifactor control of monomer sequence, molecular weight, and stereoregularity is an ultimate goal. In this work, we propose a strategy to prepare C-C main-chain sequence-regulated polymers with controlled molecular weights from vinyl monomers via a combination of iterative atom transfer radical additions and olefin metathesis reactions. This strategy enabled the synthesis of sequence-regulated polymers with exact styrene-acrylate-styrene sequences in the C-C main chains, controlled molecular weights of up to 104, and stereoregularities varying with syndiotacticity, isotacticity, and heterotacticity. The utility of this strategy is further demonstrated by formation of block copolymers consisting of sequence-regulated vinyl polymer segments by combining living ROMP of norbornene derivatives.

DOI： 10.1021/jacs.0c09289

Hypoiodite-Catalyzed Chemoselective Tandem Oxidation of Homotryptamines to Peroxy- And Epoxytetrahydropyridoindolenines Open Access

Muhammet Uyanik, Hiroki Tanaka, Kazuaki Ishihara

Organic Letters Vol. 22 ( 20 ) page： 8049 - 8054 2020.10

Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society

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

Enantio- and Site-Selective α-Fluorination of N-Acyl 3,5-Dimethylpyrazoles Catalyzed by Chiral π–CuII Complexes

Kazuaki Ishihara, Kazuki Nishimura, Katsuya Yamakawa

Angewandte Chemie - International Edition Vol. 59 ( 40 ) page： 17641 - 17647 2020.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag

Catalytic enantioselective α-fluorination reactions of carbonyl compounds are among the most powerful and efficient synthetic methods for constructing optically active α-fluorinated carbonyl compounds. Nevertheless, α-fluorination of α-nonbranched carboxylic acid derivatives is still a big challenge because of relatively high pKa values of their α-hydrogen atoms and difficulty of subsequent synthetic transformation without epimerization. Herein we show that chiral copper(II) complexes of 3-(2-naphthyl)-l-alanine-derived amides are highly effective catalysts for the enantio- and site-selective α-fluorination of N-(α-arylacetyl) and N-(α-alkylacetyl) 3,5-dimethylpyrazoles. The substrate scope of the transformation is very broad (25 examples including a quaternary α-fluorinated α-amino acid derivative). α-Fluorinated products were converted into the corresponding esters, secondary amides, tertiary amides, ketones, and alcohols with almost no epimerization in high yield.

DOI： 10.1002/anie.202007403

Enantioselective 1,4-Addition Reaction of α,β-Unsaturated Carboxylic Acids with Cycloalkanones Using Cooperative Chiral Amine–Boronic Acid Catalysts

Takahiro Horibe, Takashi Hazeyama, Yuto Nakata, Kazuki Takeda, Kazuaki Ishihara

Angewandte Chemie - International Edition Vol. 59 ( 39 ) page： 17256 - 17260 2020.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag

An enantioselective 1,4-addition of α,β-unsaturated carboxylic acids with cycloalkanones has been developed by using chiral amine–boronic acid cooperative catalysts. In the presence of a chiral amine and boronic acid, cycloalkanones and carboxylic acids are activated as chiral enamines and mixed anhydrides, respectively. The corresponding 1,4-adducts are obtained in high yield with high enantioselectivity. Furthermore, subsequent oxylactonization of the 1,4-adducts gives spirolactones with high diastereoselectivity.

DOI： 10.1002/anie.202007639

Chemo- and Enantioselective Oxidative α-Azidation of Carbonyl Compounds

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

Angewandte Chemie - International Edition Vol. 59 ( 39 ) page： 17110 - 17117 2020.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag

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

One-Pot Tandem Michael Addition/Enantioselective Conia-Ene Cyclization Mediated by Chiral Iron(III)/Silver(I) Cooperative Catalysis

Chemo‐ and Enantioselective Oxidative α‐Azidation of Carbonyl Compounds

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

Angewandte Chemie Vol. 132 ( 39 ) page： 17258 - 17265 2020.9

Takahiro Horibe, Masato Sakakibara, Rin Hiramatsu, Kazuki Takeda, Kazuaki Ishihara

Angewandte Chemie - International Edition Vol. 59 ( 38 ) page： 16470 - 16474 2020.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag

The first one-pot tandem Michael addition/enantioselective Conia-ene cyclization of N-protected prop-2-yn-1-amines with 2-methylene-3-oxoalkanoates promoted by chiral iron(III)/silver(I) cooperative catalysts has been developed. Alkyl 4-methylenepyrrolidine-3-acyl-3-carboxylates, which can be transformed into β-proline derivatives, are obtained in high yield with high enantioselectivity.

DOI： 10.1002/anie.202007180

Chemoselective oxidative generation of ortho-quinone methides and tandem transformations

Halogen-Bonding Interaction between I2and N-Iodosuccinimide in Lewis Base-Catalyzed Iodolactonization Open Access

Takahiro Horibe, Yasutaka Tsuji, Kazuaki Ishihara

Organic Letters Vol. 22 ( 12 ) page： 4888 - 4892 2020.6

Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society

The halogen-bonding interaction between I2 and N-iodosuccinimide (NIS) stabilized by a Lewis base (LB) has been explored. 1H NMR, nuclear Overhauser effect (NOE), and diffusion-ordered NMR spectroscopy (DOSY) suggest the generation of a 1:1:1 assembly, LB-I2-NIS. In contrast, when N-iodotrifluoromethanesulfonimide (INTf2) is used instead of NIS, LB-I5+-LB is generated. On the basis of these results in combination with density functional theory (DFT) calculations, we propose a mechanism for the formation of I2-NIS and the subsequent generation of an active iodinating species LB-I+.

DOI： 10.1021/acs.orglett.0c01735

One-pot Michael addition-enantioselective Conia-ene cyclization tandem reaction induced through chiral iron(III)-silver(I) cooperative catalysis Invited Reviewed

Takahiro Horibe, Masato Sakakibara, Rin Hiramatsu, Kazuki Takeda, Kazuaki Ishihara

Angew. Chem. Int. Ed. 2020.6

Muhammet Uyanik, Kohei Nishioka, Ryutaro Kondo, Kazuaki Ishihara

Nature Chemistry Vol. 12 ( 4 ) page： 353 - + 2020.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Nature Research

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. [Figure not available: see fulltext.].

DOI： 10.1038/s41557-020-0433-4