FullText URL J_Org_Chem_80_6_3111.pdf
Author Takamura, Hiroyoshi| Wada, Hiroko| Ogino, Mao| Kikuchi, Takahiro| Kadota, Isao| Uemura, Daisuke|
Abstract Four possible diastereomers of the C1-C13 fragment of symbiodinolide, which were proposed by the stereostructural analysis of the degraded product, were synthesized in a stereodivergent and stereoselective manner. The key transformations were aldol reaction of methyl acetoacetate with the aldehyde, diastereoselective reduction of the resulting β-hydroxy ketone, and the stereoinversion at the C6 position. Comparison of the (1)H NMR data between the four synthetic products and the degraded product revealed the relative stereostructure of the C1-C13 fragment of symbiodinolide.
Note This is an Accepted Manuscript of an article published by American Chemical Society This research was supported by a Grant-in Aid for Scientific Research (No. 24710250) from the Japan Society for the Promotion of Science (JSPS).
Published Date 2015-02-27
Publication Title The Journal of organic chemistry
Volume volume80
Issue issue6
Publisher American Chemical Society
Start Page 3111
End Page 3123
ISSN 00223263
NCID AA00704100
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
File Version author
PubMed ID 25723589
DOI 10.1021/acs.joc.5b00027
Web of Sience KeyUT 000351558400017
Related Url isVersionOf https://doi.org/10.1021/acs.joc.5b00027
FullText URL Org_Lett_18_9_2110.pdf
Author Takamura, Hiroyoshi| Kikuchi, Takahiro| Endo, Noriyuki| Fukuda, Yuji| Kadota, Isao|
Abstract The first total syntheses of sarcophytonolide H and the originally proposed and correct structures of isosarcophytonolide D have been achieved via transannular ring-closing metathesis (RCM). These total syntheses culminated in the stereostructural confirmation of sarcophytonolide H and the reassignment of isosarcophytonolide D, respectively. The antifouling activity of the synthetic sarcophytonolide H and its analogues was also evaluated.
Note This is an Accepted Manuscript of an article published by American Chemical Society This work was supported by Okayama Foundation for Science and Technology and JSPS KAKENHI (24710250).
Published Date 2016-05-06
Publication Title Organic Letters
Volume volume18
Issue issue9
Publisher American Chemical Society
Start Page 2110
End Page 2113
ISSN 15237060
NCID AA11347843
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
File Version author
PubMed ID 27093115
DOI 10.1021/acs.orglett.6b00737
Web of Sience KeyUT 000375891700042
Related Url isVersionOf https://doi.org/10.1021/acs.orglett.6b00737
FullText URL Org_Lett_18_17_4380.pdf
Author Murai, Masahito| Okada, Ryo| Nishiyama, Atsushi| Takai, Kazuhiko|
Abstract Use of a rhodium catalyst with (R)-(S)-BPPFA ligand allows efficient synthesis of sila[n]helicenes via dehydrogenative silylation of C-H bonds. By selecting the proper ligands, the current method provides the ability to prepare unsymmetrical sila[n]helicene derivatives without any oxidants. The resulting sila[6]helicene is a rare example of a five-membered ring-fused [6]helicene, which was isolated as a single pure enantiomer without substituents on the terminal benzene rings.
Note This is an Accepted Manuscript of an article published by American Chemical Society
Published Date 2016-08-11
Publication Title Organic Letters
Volume volume18
Issue issue17
Publisher American Chemical Society
Start Page 4380
End Page 4383
ISSN 1523-7060
NCID AA11347843
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
Copyright Holders https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
File Version author
PubMed ID 27513028
DOI 10.1021/acs.orglett.6b02134
Web of Sience KeyUT 000382711200059
Related Url https://doi.org/10.1021/acs.orglett.6b02134
FullText URL Org_Lett_18_7_1642.pdf
Author Iwasaki, Masayuki| Topolovčan, Nikola| Hu, Hao| Nishimura, Yugo| Gagnot, Glwadys| nakorn, Rungsaeng Na| Yuvacharaskul, Ramida| Nakajima, Kiyohiko| Nishihara, Yasushi|
Abstract Palladium-catalyzed carbothiolation of terminal alkynes with azolyl sulfides affords various 2-(azolyl)alkenyl sulfides with perfect regio- and stereoselectivities. The present addition reaction proceeded through a direct cleavage of carbon-sulfur bonds in azolyl sulfides. The resulting adducts that are useful intermediates in organic synthesis are further transformed to multisubstituted olefins containing azolyl moieties.
Note This is an Accepted Manuscript of an article published by American Chemical Society
Published Date 2016-03-21
Publication Title Organic Letters
Volume volume18
Issue issue7
Publisher American Chemical Society
Start Page 1642
End Page 1645
ISSN 1523-7060
NCID AA11347843
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
Copyright Holders https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
File Version author
PubMed ID 26998829
DOI 10.1021/acs.orglett.6b00503
Web of Sience KeyUT 000373519600037
Related Url https://doi.org/10.1021/acs.orglett.6b00503
FullText URL Org_Lett_18_9_2020.pdf
Author Morimoto, Naoki| Morioku, Kumika| Suzuki, Hideyuki| Takeuchi, Yasuo| Nishina, Yuta|
Abstract Indole readily undergoes nucleophilic substitution at the C3 site, and many indole derivatives have been functionalized using this property. Indole also forms indolium, which allows electrophilic addition in acidic conditions, but current examples have been limited to intramolecular reactions. C2 site-selective nucleophilic addition to indole derivatives using fluoroalcohol and a Lewis acid was developed.
Note This is an Accepted Manuscript of an article published by American Chemical Society
Published Date 2016-04-27
Publication Title Organic Letters
Volume volume18
Issue issue9
Publisher American Chemical Society
Start Page 2020
End Page 2023
ISSN 1523-7060
NCID AA11347843
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
Copyright Holders https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
File Version author
PubMed ID 27119318
DOI 10.1021/acs.orglett.6b00629
Web of Sience KeyUT 000375891700019
Related Url https://doi.org/10.1021/acs.orglett.6b00629
FullText URL Org_Lett_19_5_1092.pdf
Author Iwasaki, Masayuki| Miki, Natsumi| Tsuchiya, Yuta| Nakajima, Kiyohiko| Nishihara, Yasushi|
Abstract Nickel-catalyzed direct selenation of benzamides bearing an 8-quinolyl auxiliary with elemental selenium provides benzoisoselenazolones in good yield via carbon-selenium and nitrogen-selenium bond formation under aerobic conditions. In addition to aryl C-H bonds, the method can also be applied to alkenyl C-H bonds, constructing an isoselenazolone skeleton. Simple mechanistic analysis shows that the reaction proceeds through a rate-determining C-H bond cleavage. The obtained benzoisoselenazolones are transformed into various organoselenium compounds and utilized as the catalyst for bromolactonization of alkenoic acids.
Note This is an Accepted Manuscript of an article published by American Chemical Society
Published Date 2017-02-17
Publication Title Organic Letters
Volume volume19
Issue issue5
Publisher American Chemical Society
Start Page 1092
End Page 1095
ISSN 1523-7060
NCID AA11347843
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
Copyright Holders https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
File Version author
PubMed ID 28211695
DOI 10.1021/acs.orglett.7b00116
Web of Sience KeyUT 000395726100032
Related Url https://doi.org/10.1021/acs.orglett.7b00116
FullText URL Chem_Mater_29_5_2150.pdf
Author Morimoto, Naoki| Suzuki, Hideyuki| Takeuchi, Yasuo| Kawaguchi, Shogo| Kunisu, Masahiro| Bielawski, Christopher W.| Nishina, Yuta|
Abstract Graphite oxide (GO) and its constituent layers (i.e., graphene oxide) display a broad range of functional groups and, as such, have attracted significant attention for use in numerous applications. GO is commonly prepared using the “Hummers method” or a variant thereof in which graphite is treated with KMnO4 and various additives in H2SO4. Despite its omnipresence, the underlying chemistry of such oxidation reactions is not well understood and typically affords results that are irreproducible and, in some cases, unsafe. To overcome these limitations, the oxidation of graphite under Hummers-type conditions was monitored over time using in situ X-ray diffraction and in situ X-ray absorption near edge structure analyses with synchrotron radiation. In conjunction with other atomic absorption spectroscopy, UV–vis spectroscopy and elemental analysis measurements, the underlying mechanism of the oxidation reaction was elucidated, and the reaction conditions were optimized. Ultimately, the methodology for reproducibly preparing GO on large scales using only graphite, H2SO4, and KMnO4 was developed and successfully adapted for use in continuous flow systems.
Published Date 2017-03-02
Publication Title Chemistry of Materials
Volume volume29
Issue issue5
Publisher American Chemical Society
Start Page 2150
End Page 2156
ISSN 15205002
NCID AA12096771
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
Copyright Holders Copyright © 2017 American Chemical Society
File Version author
DOI 10.1021/acs.chemmater.6b04807
Web of Sience KeyUT 000396639400027
Related Url isVersionOf https://doi.org/10.1021/acs.chemmater.6b04807
FullText URL JoAmChemSoc_2017_139_12_4376.pdf
Author Niho, Akiko| Yoshizawa, Susumu| Tsukamoto, Takashi| Kurihara, Marie| Tahara, Shinya| Nakajima, Yu| Mizuno, Misao| Kuramochi, Hikaru| Tahara, Tahei| Mizutani, Yasuhisa| Sudo, Yuki|
Abstract In organisms, ion transporters play essential roles in the generation and dissipation of ion gradients across cell membranes. Microbial rhodopsins selectively transport cognate ions using solar energy, in which the substrate ions identified to date have been confined to monovalent ions such as H+, Na+, and Cl-. Here we report a novel rhodopsin from the cyanobacterium Synechocystis sp. PCC 7509, which inwardly transports a polyatomic divalent sulfate ion, SO42-, with changes of its spectroscopic properties in both unphotolyzed and photolyzed states. Upon illumination, cells expressing the novel rhodopsin, named Synechocystis halorhodopsin (SyHR), showed alkalization of the medium only in the presence of Cl- or SO42-. That alkalization signal was enhanced by addition of a protonophore, indicating an inward transport of Cl- and SO42- with a subsequent secondary inward H+ movement across the membrane. The anion binding to SyHR was suggested by absorption spectral shifts from 542 to 536 nm for Cl- and from 542 to 556 nm for SO42-, and the affinities of Cl- and SO42- were estimated as 0.112 and 5.81 mM, respectively. We then performed time-resolved spectroscopic measurements ranging from femtosecond to millisecond time domains to elucidate the structure and structural changes of SyHR during the photoreaction. Based on the results, we propose a photocycle model for SyHR in the absence or presence of substrate ions with the timing of their uptake and release. Thus, we demonstrate SyHR as the first light-driven polyatomic divalent anion (SO42-) transporter and report its spectroscopic characteristics.
Note This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © American Chemical Society after peer review and technical editing by the publisher.
Published Date 2017-03-29
Publication Title Journal of the American Chemical Society
Volume volume139
Issue issue12
Publisher American Chemical Society
Start Page 4376
End Page 4389
ISSN 00027863
NCID AA00692602
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
File Version author
PubMed ID 28257611
DOI 10.1021/jacs.6b12139
Web of Sience KeyUT 000398247100034
Related Url isVersionOf https://doi.org/10.1021/jacs.6b12139