Yuji Mori

Find an error

Name:

Organization: Meijo University

Department: Faculty of Pharmacy

Title:

TOPICS

Organic Chemistry

allene

Chemicals
References

CAr–O Rotamers in 3,3′-Disubstituted BINOL Esters

Co-reporter:Takeo Sakai, Junpei Matsuoka, Masayuki Shintai, and Yuji Mori

The Journal of Organic Chemistry March 17, 2017 Volume 82(Issue 6) pp:3276-3276

Publication Date(Web):February 22, 2017

DOI:10.1021/acs.joc.6b03035

Rotamers around the CAr–O bond were disclosed in 3,3′-disubstituted BINOL esters by NMR spectroscopy. A bulky R1 group increased the rotational barrier. The pivalate showed two rotamers at 2 °C, and broad signals were observed close to room temperature when R2 = Ph. The highest rotational barrier was recorded for the (tetracyanocyclopentadienyl)carboxylate, and C–O rotamers were present at room temperature. DFT calculations indicated the presence of repulsion between R1 and R2 during rotation of the CAr–O bond.

Synthesis of the KLMN Fragment of Gymnocin-A from the FGH Fragment

Co-reporter:Takeo Sakai, Aoi Ishihara, and Yuji Mori

The Journal of Organic Chemistry April 7, 2017 Volume 82(Issue 7) pp:3976-3976

Publication Date(Web):March 9, 2017

DOI:10.1021/acs.joc.7b00232

An improved route for the synthesis of the KLMN fragment of gymnocin-A was developed through the oxiranyl anion coupling of the FGH fragment with a chiral C3 epoxy sulfone, followed by 6-endo cyclization. This straightforward approach reduced the number of synthetic steps by 14 compared with a previous route using alternative building blocks.

Total Synthesis of Brevisamide Using an Oxiranyl Anion Strategy

Co-reporter:Takeo Sakai, Ayumi Fukuta, Kumiko Nakamura, Masato Nakano, and Yuji Mori

The Journal of Organic Chemistry 2016 Volume 81(Issue 9) pp:3799-3808

Publication Date(Web):April 8, 2016

DOI:10.1021/acs.joc.6b00484

A total synthesis of brevisamide, a marine monocyclic ether amide isolated from the dinoflagellate Karenia brevis, has been achieved in 18 steps starting from 4-(benzyloxy)butanol. The synthesis involves oxiranyl anion coupling between an epoxy sulfone and a triflate, intramolecular etherification of a hydroxy-bromoketone, diastereoselective introduction of the axial methyl group by hydroxyl-directed hydrogenation of an exocyclic olefin, and installation of an acetamide side chain by nucleophilic substitution of an N-acetyl carbamate. The dienal side chain is assembled using a Horner–Wadsworth–Emmons reaction to complete the synthesis.

Total Synthesis of Gymnocin-A

Co-reporter:Takeo Sakai; Shingo Matsushita; Shogo Arakawa; Koichi Mori; Miki Tanimoto; Akihiro Tokumasu; Tatsuji Yoshida

Journal of the American Chemical Society 2015 Volume 137(Issue 45) pp:14513-14516

Publication Date(Web):November 1, 2015

DOI:10.1021/jacs.5b10082

A convergent total synthesis of cytotoxic marine natural polycyclic ether, gymnocin-A (1), is described. The synthesis features three iterations of an oxiranyl anion strategy, involving base-mediated cycloetherification, ring expansion, and reductive etherification, for the construction of the FGH fragment and for its coupling with the ABC and KLMN fragments.

Synthesis of the KLMN Fragment of Gymnocin-A Using Oxiranyl Anion Convergent Methodology

Co-reporter:Takeo Sakai, Haruka Asano, Kyoko Furukawa, Rie Oshima, and Yuji Mori

Organic Letters 2014 Volume 16(Issue 8) pp:2268-2271

Publication Date(Web):April 9, 2014

DOI:10.1021/ol500788c

Synthesis of the KLMN fragment of gymnocin-A has been achieved by a [X + 2 + Y]-type convergent strategy involving the coupling of a K-ring triflate and an N-ring epoxy sulfone. Fusions of the L ring and the M ring were carried out by intramolecular SN2 substitution of a tertiary alcohol and reductive etherification to furnish the target molecule.

Synthetic study of gymnocin-A: synthesis of the ABC ring fragment

Co-reporter:Takeo Sakai, Shingo Matsushita, Shogo Arakawa, Atsuko Kawai, Yuji Mori

Tetrahedron Letters 2014 Volume 55(Issue 48) pp:6557-6560

Publication Date(Web):26 November 2014

DOI:10.1016/j.tetlet.2014.10.014

The synthesis of the ABC ring fragment of gymnocin-A is described. The key feature of this approach was the convergent BC ring formation using an oxiranyl anion coupling, which was followed by intramolecular Williamson ether synthesis and the reductive etherification of an α-acetoxy acetal. The five-membered A ring was then constructed on the seven-membered B ring by radical cyclization of a β-alkoxy acrylate derivative.

Synthesis of fused tetrahydropyrans by hydroalkoxylation of δ-hydroxy allenes

Co-reporter:Yumie Suzuki, Ayano Kuwabara, Yasuhiro Koizumi, Yuji Mori

Tetrahedron 2013 69(43) pp: 9086-9095

Publication Date(Web):

DOI:10.1016/j.tet.2013.08.026

Synthesis of Functionalized Tetracyanocyclopentadienides from Tetracyanothiophene and Sulfones

Co-reporter:Takeo Sakai, Shohei Seo, Junpei Matsuoka, and Yuji Mori

The Journal of Organic Chemistry 2013 Volume 78(Issue 21) pp:10978-10985

Publication Date(Web):October 4, 2013

DOI:10.1021/jo401946j

Tetracyanothiophene and tetracyano-1,4-dithiin react with a leaving group substituted carbon nucleophile such as ethyl benzenesulfonylacetate to afford substituted tetracyanocyclopentadienyl sodium derivatives in moderate to high yields through a putative condensation and desulfurization pathway. Subsequent functional-group transformation reactions on the Cp anion ring provided various C5R(CN)4– derivatives.

Mechanism of the Regio- and Diastereoselective Ring Expansion Reaction Using Trimethylsilyldiazomethane

Co-reporter:Takeo Sakai, Satoshi Ito, Hiroki Furuta, Yuki Kawahara, and Yuji Mori

Organic Letters 2012 Volume 14(Issue 17) pp:4564-4567

Publication Date(Web):August 17, 2012

DOI:10.1021/ol302032w

An equatorial attack of TMS-diazomethane was determined to be the first step of the BF3-promoted ring expansion reaction of six-membered ketones using TMS-diazomethane. The migration reaction occurred in a conformation in which the carbonyl oxygen and the TMS group were antiperiplanar to predominantly afford trans-seven-membered ketones.

Divergent Synthesis of Trans-Fused Polycyclic Ethers by a Convergent Oxiranyl Anion Strategy

Co-reporter:Takeo Sakai, Ai Sugimoto, Hiroki Tatematsu, and Yuji Mori

The Journal of Organic Chemistry 2012 Volume 77(Issue 24) pp:11177-11191

Publication Date(Web):December 5, 2012

DOI:10.1021/jo302267f

Octacyclic polyethers that correspond to the CDEFGHIJ-ring system of yessotoxin as well as G- and/or I-ring-modified analogues were synthesized in a divergent manner, starting from a common intermediate, using an [X + 2 + Y]-type convergent method. Reaction of a triflate with the oxiranyl anion generated from an epoxy sulfone, followed by ring expansion, allowed for the incorporation of medium-sized ring ethers into the key intermediate. Subsequent acetal formation and reductive etherification afforded various octacycles containing seven- and eight-membered ether rings.

A Convergent Strategy for the Synthesis of Polycyclic Ethers by Using Oxiranyl Anions

Co-reporter:Takeo Sakai, Ai Sugimoto, and Yuji Mori

Organic Letters 2011 Volume 13(Issue 21) pp:5850-5853

Publication Date(Web):October 6, 2011

DOI:10.1021/ol202467z

A new [X+2+Y]-type for the convergent synthesis of polycyclic ethers based on an oxiranyl anion strategy was developed. The sequence involves nucleophilic substitution of a triflate with an oxiranyl anion followed by 6-endo cyclization, ring expansion, and reductive etherification. The protocol features a flexible approach toward trans-fused polycyclic arrays consisting of six- and seven-membered ether rings from the same starting materials.

Total Synthesis of Gambierol by Using Oxiranyl Anions

Co-reporter:Hiroki Furuta Dr.;Yuki Hasegawa;Mariko Hase

Chemistry - A European Journal 2010 Volume 16( Issue 25) pp:7586-7595

Publication Date(Web):

DOI:10.1002/chem.201000497

Abstract

Gambierol was isolated as a neurotoxin from the cultured cells of the ciguatera causative dinoflagellate Gambierdiscus toxicus and classified as a member of the polycyclic ether family of marine toxins. The structure consists of a ladder-shaped trans-fused octacyclic ring system that includes 18 stereogenic centers, two 1,3-diaxial dimethyl-substituted tetrahydropyranyl rings, and a partially conjugated triene side chain. The total synthesis of gambierol has been achieved by utilizing an oxiranyl anion strategy in an iterative manner. Synthetic highlights of this route include direct carbon–carbon formation on epoxides, sulfonyl-assisted 6-endo cyclization, and an expansion reaction of the tetrahydropyranyl rings to oxepanes to forge the polycyclic architecture of the target molecule.

Reiterative Synthesis of trans-Fused Polytetrahydropyrans Using the Oxiranyl Anion

Co-reporter:Yuji Mori

Chemistry - A European Journal 1997 Volume 3(Issue 6) pp:

Publication Date(Web):21 JAN 2006

DOI:10.1002/chem.19970030604

The oxiranyl anion is a very unstable nucleophilic epoxide. This previously uncommon nucleophile has now been used for the synthesis of polycyclic ethers. Alkylation of an oxiranyl anion, a three-carbon building block, with a triflate derived from tetrahydropyran-methanol followed by acid-catalyzed 6-endo cyclization provides a trans-fused bicyclic compound. Reiterative application of this procedure enables the rapid construction of trans-fused polytetrahydropyrans.