Faculty Profiles - ISHIHARA Kazuaki

Papers - ISHIHARA Kazuaki

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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

Chemoselective oxidative generation of ortho-quinone methides and tandem transformations

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

Web of Science

Scopus

PubMed

Visual Feedback Control of a Rat Ankle Angle Using a Wirelessly Powered Two-Channel Neurostimulator Open Access

Takeuchi, M; Watanabe, K; Ishihara, K; Miyamoto, T; Tokutake, K; Saeki, S; Aoyama, T; Hasegawa, Y; Kurimoto, S; Hirata, H

SENSORS Vol. 20 ( 8 ) 2020.4

Cationic Iron(III) Salt as an Initiator for Radical Cation-induced [4+2] Cycloaddition

Takahiro Horibe, Shuhei Ohmura, Kei Katagiri, Kazuaki Ishihara

Asian Journal of Organic Chemistry Vol. 9 ( 3 ) page： 395 - 398 2020.3

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

We developed a cationic iron(III) salt initiator for radical cation-induced [4+2] cycloaddition. Fe(OTf)3 [or Fe(ClO4)3] behaves as a highly active oxidant for both electron-deficient and electron-rich dienophiles. The scope of substrates is much broader than with FeCl3 reported previously. With highly active Fe(OTf)3, we demonstrate a formal total synthesis of Heitziamide A.

DOI： 10.1002/ajoc.201900749

Scopus

Radical-Cation-Induced Crossed [2+2] Cycloaddition of Electron-Deficient Anetholes Initiated by Iron(III) Salt Open Access

Takahiro Horibe, Kei Katagiri, Kazuaki Ishihara

Advanced Synthesis and Catalysis Vol. 362 ( 4 ) page： 960 - 963 2020.2

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

Radical cation-induced crossed [2+2] cycloaddition of electron-deficient anetholes was developed with the use of Fe(OTf)3 as an initiator. Various 1,2-diarylcyclobutanes can be synthesized in high yields with high diastereoselectivity from electron-deficient anetholes, which have been less explored using conventional methods. This practical reaction system can be used for a decagram-scale reaction (12 gram), in which the resulting product can be transformed to 1,2-dicarbonyl compounds. (Figure presented.).

DOI： 10.1002/adsc.201901337

Open Access

Web of Science

Scopus

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

Muhammet Uyanik, Naoto Sahara, Outa Katade, Kazuaki Ishihara

Organic Letters Vol. 22 ( 2 ) page： 560 - 564 2020.1

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

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

Web of Science

Scopus

PubMed

Initiators for radical cation-induced [2 + 2]- and [4 + 2]-cycloadditions of electron-rich Alkenes Open Access

Takahiro Horibe, Kazuaki Ishihara

Chemistry Letters Vol. 49 ( 1 ) page： 107 - 113 2020.1

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

The radical cation-induced [2 + 2]- and [4 + 2]-cycloadditions of electron-rich alkenes afford cyclobutanes and cyclohexenes, which are used in the synthesis of natural products. The key intermediate is the alkene radical cation, which is generated from alkene by a one-electron oxidant. These cycloadditions have attracted renewed attention thanks to the recent development of initiators, such as a chemical oxidant, an electrochemical method and photoredox catalysts. This Highlight Review summarizes these initiators for [2 + 2]- and [4 + 2]-cycloadditions that leverage the generation of the alkene radical cation.

DOI： 10.1246/cl.190790

Web of Science

Scopus

An enantioselective oxidative coupling reaction of 2-naphthol derivatives catalyzed by chiral diphosphine oxide-iron(ii) complexes Open Access

Takahiro Horibe, Keita Nakagawa, Takashi Hazeyama, Kazuki Takeda, Kazuaki Ishihara

Chemical Communications Vol. 55 ( 91 ) page： 13677 - 13680 2019.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Royal Society of Chemistry

An enantioselective oxidative coupling of 2-naphthol derivatives is developed with the use of chiral Fe(ii)-diphosphine oxide complexes. Optically active 1,1-bi-2-naphthol derivatives can be synthesized in high yields when a 2 : 1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2 is used in the presence of t-butyl hydroperoxide as an oxidant. The non-linear effect, X-ray crystal structure and ESI-MS suggest that a 2 : 1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2 is a pre-catalyst for a Fe(iii)/Fe(iv) redox cycle.

DOI： 10.1039/c9cc07834g

High-performance ammonium hypoiodite/Oxone catalysis for enantioselective oxidative dearomatization of arenols Reviewed

Muhammet Uyanik, Takehiro Kato, Naoto Sahara, Outa Katade, Kazuaki Ishihara

ACS Catal. Vol. 9 ( 12 ) page： 11619-11626 2019.11

ホウ素Lewis酸—キラルリン酸複合触媒を用いるマルチ選択的[2+2]/[4+2]付加環化反応 Invited Reviewed

波多野学，石原一彰

化学工業 Vol. 70 ( 9 ) page： 634-642 2019.9

Highly Active Chiral Dilithium(I) Binaphthyldisulfonate Catalysts for Enantio- and Chemoselective Strecker-Type Reactions

Manabu Hatano, Kosuke Nishio, Takuya Mochizuki, Keisuke Nishikawa, Kazuaki Ishihara

ACS Catalysis Vol. 9 ( 9 ) page： 8178 - 8186 2019.9

Highly active chiral dilithium(I) binaphthyldisulfonate catalysts for enantio- and chemoselective Strecker-type reactions

Manabu Hatano, Kosuke Nishio, Takuya Mochizuki, Keisuke Nishikawa, Kazuaki Ishihara

ACS Catal. Vol. 9 ( 9 ) page： 8178-8196 2019.7

Tris(pentafluorophenyl)borane‐Assisted Chiral Phosphoric Acid Catalysts for Enantioselective Inverse‐Electron‐Demand Hetero‐Diels‐Alder Reaction of α,β‐Substituted Acroleins Open Access

Manabu Hatano, Tatsuhiro Sakamoto, Takuya Mochizuki, Kazuaki Ishihara

Asian Journal of Organic Chemistry Vol. 8 ( 7 ) page： 1061 - 1066 2019.7

Front Cover: Tris(pentafluorophenyl)borane‐Assisted Chiral Phosphoric Acid Catalysts for Enantioselective Inverse‐Electron‐Demand Hetero‐Diels‐Alder Reaction of α,β‐Substituted Acroleins (Asian J. Org. Chem. 7/2019)

Manabu Hatano, Tatsuhiro Sakamoto, Takuya Mochizuki, Kazuaki Ishihara

Asian Journal of Organic Chemistry Vol. 8 ( 7 ) page： 918 - 918 2019.7