Hidenori Watanabe *

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Organization: The University of Tokyo

Department: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences

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TOPICS

Organic Chemistry

Asymmetric Synthesis

Chemicals
References

Synthesis of (−)-okundoperoxide and determination of the absolute configuration of natural (+)-okundoperoxide

Co-reporter:Naoki Mori, Daichi Sakoda, Hidenori Watanabe

Tetrahedron Letters 2017 Volume 58, Issue 40(Issue 40) pp:

Publication Date(Web):4 October 2017

DOI:10.1016/j.tetlet.2017.08.064

•The first enantioselective synthesis of (−)-okundoperoxide has been accomplished.•The absolute configuration of okundoperoxide has been determined.•The peroxy moiety was installed by a singlet oxygen [4+2] cycloaddition reaction.•Reaction of the hydroperoxide with the vinyl epoxide gave the desired peroxide ring.The first enantioselective synthesis of (3S,4aR,8aR)-1 (the enantiomer of natural okundoperoxide) has been accomplished. The synthesis features: 1) stereoselective installation of the peroxy functionality (16 → 17); 2) ring opening of peroxyacetal and subsequent intramolecular reaction between the hydroperoxide and the vinyl epoxide to form the peroxy six-membered ring (5 → 1). The absolute configuration of okundoperoxide was determined to be 3R,4aS,8aS by comparing specific rotations of the synthetic sample and the natural product.Download high-res image (26KB)Download full-size image

First total synthesis of glabramycin B and revision of its relative configuration

Co-reporter:Masaoki Yamamoto, Ken Ishigami, Hidenori Watanabe

Tetrahedron 2017 Volume 73, Issue 23(Issue 23) pp:

Publication Date(Web):8 June 2017

DOI:10.1016/j.tet.2017.04.061

Structural revision of glabramycin B, which is an antibacterial 10-membered lactone isolated from a fermentation broth of Neosartorya glabra, was achieved by enantioselective synthesis of our proposed structure. The correct structure of glabramycin B was presumed on comparison with related compounds, and synthesis of it was succeeded via dianion alkylation, Shiina's lactonization and Stille cross-coupling. By this synthesis, we were able to correct the reported structural misassignment, and to confirm the relative configuration of glabramycin B to be 10S*,11S*,15R*,20S*.Download high-res image (117KB)Download full-size image

Stereoselective synthesis of (±)-urechitol A employing [4+3] cycloaddition

Co-reporter:Tatsunobu Sumiya, Ken Ishigami, Hidenori Watanabe

Tetrahedron 2016 Volume 72(Issue 44) pp:6982-6987

Publication Date(Web):3 November 2016

DOI:10.1016/j.tet.2016.09.026

Urechitol A was synthesized as a racemate employing a [4+3] cycloaddition reaction and a methanol assisted intramolecular epoxide opening as key steps for efficient construction of the core tricyclic framework. The overall yield was 2.4% over 12 steps.

Synthesis of (−)-Chamobtusin A from (+)-Dehydroabietylamine

Co-reporter:Naoki Mori, Kazuma Kuzuya, and Hidenori Watanabe

The Journal of Organic Chemistry 2016 Volume 81(Issue 23) pp:11866-11870

Publication Date(Web):October 21, 2016

DOI:10.1021/acs.joc.6b02328

Chamobtusin A, a unique diterpene alkaloid isolated from Chamaecyparis obtusa cv. tetragon, is considered to be biosynthesized from an abietane diterpenoid. On the basis of this biosynthetic hypothesis, ferruginol (15) was synthesized from (+)-dehydroabietylamine and then biomimetically transformed into (−)-chamobtusin A in 6 steps (12 steps from (+)-dehydroabietylamine).

Electochemical asymmetric dimerization of cinnamic acid derivatives and application to the enantioselective syntheses of furofuran lignans

Co-reporter:Naoki Mori, Akiko Furuta, Hidenori Watanabe

Tetrahedron 2016 Volume 72(Issue 51) pp:8393-8399

Publication Date(Web):22 December 2016

DOI:10.1016/j.tet.2016.10.058

A new electrochemical method for the asymmetric oxidative dimerization of cinnamic acid derivatives has been developed. This method enabled the enantioselective syntheses of furofuran lignans, yangambin, sesamin and eudesmin.

Synthesis and revision of the relative configuration of glabramycin B

Co-reporter:Ken Ishigami, Masaoki Yamamoto, Hidenori Watanabe

Tetrahedron Letters 2015 Volume 56(Issue 45) pp:6290-6293

Publication Date(Web):4 November 2015

DOI:10.1016/j.tetlet.2015.09.149

The stereostructure of glabramycin B, which is an antibacterial 10-membered lactone fused with 4-oxygenated cyclohexanone, was presumed on comparison with related compounds, and concise synthesis of our proposed structure of glabramycin B was achieved via dianion alkylation, Shiina’s lactonization, and Stille cross coupling. We succeeded in the reassignment of its relative configuration.

Asymmetric Formal Synthesis of Azadirachtin

Co-reporter:Dr. Naoki Mori;Dr. Takeshi Kitahara;Dr. Kenji Mori;Dr. Hidenori Watanabe

Angewandte Chemie 2015 Volume 127( Issue 49) pp:15133-15136

Publication Date(Web):

DOI:10.1002/ange.201507935

Abstract

An asymmetric formal synthesis of azadirachtin, a potent insect antifeedant, was accomplished in 30 steps to Ley’s synthetic intermediate (longest linear sequence). The synthesis features: 1) rapid access to the optically active right-hand segment starting from the known 5-hydroxymethyl-2-cyclopentenone scaffold; 2) construction of the B and E rings by a key intramolecular tandem radical cyclization; 3) formation of the hemiacetal moiety in the C ring through the α-oxidation of the six-membered lactone followed by methanolysis.

Asymmetric Formal Synthesis of Azadirachtin

Co-reporter:Dr. Naoki Mori;Dr. Takeshi Kitahara;Dr. Kenji Mori;Dr. Hidenori Watanabe

Angewandte Chemie International Edition 2015 Volume 54( Issue 49) pp:14920-14923

Publication Date(Web):

DOI:10.1002/anie.201507935

Abstract

Total synthesis of (±)-lysidicin A

Co-reporter:Yusuke Ogura, Ken Ishigami, Hidenori Watanabe

Tetrahedron 2012 68(6) pp: 1723-1728

Publication Date(Web):

DOI:10.1016/j.tet.2011.12.062

Synthesis and sensory evaluation of all stereoisomers of sedanolide

Co-reporter:Daichi Oguro, Hidenori Watanabe

Tetrahedron 2011 67(4) pp: 777-781

Publication Date(Web):

DOI:10.1016/j.tet.2010.11.035

Synthesis of (±)-Chamobtusin A by a Presumed Biomimetic Aza-Cyclization

Co-reporter:Kazuma Kuzuya, Naoki Mori, and Hidenori Watanabe

Organic Letters 2010 Volume 12(Issue 21) pp:4709-4711

Publication Date(Web):September 29, 2010

DOI:10.1021/ol101846z

A total synthesis of (±)-chamobtusin A has been accomplished on the basis of our presumed biosynthetic pathway: the imine formation of keto aldehyde followed by intramolecular aza-Michael addition.

Efficient construction of the core framework of lysidicin A via three Claisen rearrangements including a cascade reaction

Co-reporter:Yusuke Ogura, Hidenori Watanabe

Tetrahedron Letters 2010 Volume 51(Issue 25) pp:3294-3296

Publication Date(Web):23 June 2010

DOI:10.1016/j.tetlet.2010.04.073

A model compound (6) with the core skeleton of lysidicin A was synthesized as a racemate. The key step (8→7) includes three Claisen rearrangements of the triether with phloroglucinols; two of which rearranged in a cascade manner and the other was a simple rearrangement. This one-pot reaction enabled the introduction of three phloroglucinol units at the correct positions and makes the synthetic approach significantly efficient.

Determination of the absolute configuration of marine oxylipin topsentolide A1 by the synthesis of the enantiomer of the natural product

Co-reporter:Munetaka Kobayashi, Ken Ishigami, Hidenori Watanabe

Tetrahedron Letters 2010 Volume 51(Issue 20) pp:2762-2764

Publication Date(Web):19 May 2010

DOI:10.1016/j.tetlet.2010.03.071

Two possible stereoisomers of topsentolide A1, a cytotoxic oxylipin against human solid tumor cell lines, were prepared in order to determine the stereochemistry of natural product. That is, the enantiomer of topsentolide A1, (8S,11S,12R)-isomer, and its diastereomer was efficiently synthesized in a stereoselective manner. The stereochemistry of topsentolide A1 was determined to be 8R,11R,12S by comparing NMR spectra and specific rotations of the synthetic isomers and the natural product.

Determination of the absolute configuration of nodulisporacid A by the concise synthesis of four stereoisomers via three-component reaction and one-pot construction of the framework

Co-reporter:Tatsunobu Sumiya, Ken Ishigami, Hidenori Watanabe

Tetrahedron Letters 2010 Volume 51(Issue 20) pp:2765-2767

Publication Date(Web):19 May 2010

DOI:10.1016/j.tetlet.2010.03.064

Four stereoisomers of nodulisporacid A (1) were synthesized by the concise approach which includes three-component reaction and subsequent one-pot construction of the whole framework. The 1H NMR comparison of the derivatives (10–12) revealed the absolute configuration of natural 1 to be 4R,4′R,6′R.

Stereoselective Total Synthsis of ()-UrechitolA

Co-reporter:Tatsunobu Sumiya;Ken Ishigami Dr.;Hidenori Watanabe Dr.

Angewandte Chemie International Edition 2010 Volume 49( Issue 32) pp:5527-5528

Publication Date(Web):

DOI:10.1002/anie.201002505

Stereoselective Total Synthsis of ()-UrechitolA

Co-reporter:Tatsunobu Sumiya;Ken Ishigami Dr.;Hidenori Watanabe Dr.

Angewandte Chemie 2010 Volume 122( Issue 32) pp:5659-5660

Publication Date(Web):

DOI:10.1002/ange.201002505

Synthesis and structure revision of tyroscherin, and bioactivities of its stereoisomers against IGF-1-dependent tumor cells

Co-reporter:Ken Ishigami, Ryo Katsuta, Chié Shibata, Yoichi Hayakawa, Hidenori Watanabe, Takeshi Kitahara

Tetrahedron 2009 65(18) pp: 3629-3638

Publication Date(Web):

DOI:10.1016/j.tet.2009.03.003

Synthetic Study Towards Azadirachtin: An Efficient and Stereoselective Construction of the AB Rings with Full Functionality

Co-reporter:Hidenori Watanabe Dr.;Naoki Mori;Daisuke Itoh Dr.;Takeshi Kitahara Dr.;Kenji Mori Dr.

Angewandte Chemie 2007 Volume 119(Issue 9) pp:

Publication Date(Web):17 JAN 2007

DOI:10.1002/ange.200604097

Von A nach B: Die Decalineinheit von Azadirachtin, die das vollständig funktionalisierte AB-Ringsystem umfasst (siehe Bild), wurde stereoselektiv in nur 23 Stufen synthetisiert. Schlüsselschritte sind eine intramolekulare Diels-Alder-Reaktion, eine Decarboxylierung, eine Claisen-Umlagerung und schließlich eine Tandem-Radikalcyclisierung.

Synthetic Study Towards Azadirachtin: An Efficient and Stereoselective Construction of the AB Rings with Full Functionality

Co-reporter:Hidenori Watanabe Dr.;Naoki Mori;Daisuke Itoh Dr.;Takeshi Kitahara Dr.;Kenji Mori Dr.

Angewandte Chemie International Edition 2007 Volume 46(Issue 9) pp:

Publication Date(Web):17 JAN 2007

DOI:10.1002/anie.200604097

From A to B: The decalin moiety of azadirachtin, which includes the fully functionalized AB ring system (see picture), was synthesized stereoselectively in only 23 steps. Key steps include an intramolecular Diels–Alder reaction, a decarboxylation, a Claisen rearrangement, and finally a tandem radical cyclization.

Novel asymmetric oxy-michael addition reaction of the chiral ketones to the achiral γ- or δ-hydroxy-α,β-unsaturated carbonyl compounds

Co-reporter:Hidenori Watanabe;Kaori Machida;Daisuke Itoh;Haruki Nagatsuka;Takeshi Kitahara

Chirality 2001 Volume 13(Issue 7) pp:379-385

Publication Date(Web):22 JUN 2001

DOI:10.1002/chir.1048

A novel asymmetric oxy-Michael addition reaction was developed. In the presence of a catalytic amount of base, chiral ketones 1 and 2, derived from D-glucose and D-fructose, respectively, reacted with ω-hydroxy enones or enoates 3a–e, 17 and 21 to form the hemiacetal-derived alkoxide which underwent stereoselective intramolecular Michael addition to give cyclic acetals. Although the stereoselectivities in the formation of the five-membered acetal rings were modest, six-membered ring formation proceeded with high stereoselectivity and the utility of the reaction was demonstrated by a simple syntheses of natural products. Chirality 13:379–385, 2001. © 2001 Wiley-Liss, Inc.

31,32,33,34,35,36-Hexaazaheptacyclo[26.2.1.13,6.18,11.113,16.118,21.123,26]hexatriaconta-1(31),2,4,6,8,10,12,14,16(34),17,19,21,23,25,27,29-hexadecaene, 2,7,12,17,22,27-hexakis(2,3,4,5,6-pentafluorophenyl)-4,5,14,15,24,25-hexaphenyl-

CAS:1595241-61-4

31,32,33,34,35,36-Hexaazaheptacyclo[26.2.1.13,6.18,11.113,16.118,21.123,26]hexatriaconta-1(31),2,4,6,8,10,12,14,16(34),17,19,21,23,25,27,29-hexadecaene, 2,7,12,17,22,27-hexakis(2,3,4,5,6-pentafluorophenyl)-4,5,14,15,24,25-hexaphenyl-