Yasufumi Ohfune
Osaka City University
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Publication
Featured researches published by Yasufumi Ohfune.
Organic Letters | 2009
Toyomi Kotaki; Tetsuro Shinada; Kanako Kaihara; Yasufumi Ohfune; Hideharu Numata
The structure of the juvenile hormone (JH) in the suborder Heteroptera, order Hemiptera, has been known for a very long time to be different from the JH of other orders, but the structure has been a matter of controversy. The structure was first elucidated by an unprecedented approach involving the screening of a JH molecular library. The novel Heteroptera-specific JH (JHSB3) is a new category of JH that is featured by the skipped bisepoxide structure.
Organic Letters | 2008
Kazuhiko Sakaguchi; Miki Ayabe; Yusuke Watanabe; Takuya Okada; Kazushige Kawamura; Tetsuro Shiada; Yasufumi Ohfune
The stereoselective total synthesis of the marine alkaloid (-)-amathaspiramide F (1) was achieved from the alpha-hydoxy-alpha-ethynylsilane 2. The crucial steps in this synthesis involved not only the enolate Claisen rearrangement of the alpha-acyloxy-alpha-alkenylsilane 6 for the construction of the nitrogen-containing quaternary carbon center, but also the chemoselective formation of the azaspirohemiaminal 12 using heptamethyldisilazane as the methylamine equivalent and the regioselective dibromination of the phenol moiety of 12 using n-Bu(4)NBrCl(2).
Organic Letters | 2009
Makoto Hamada; Tetsuro Shinada; Yasufumi Ohfune
A highly diastereoselective total synthesis of (-)-kaitocephalin, a novel antagonist of ionotropic glutamate receptors, was accomplished in 12 steps starting from 5-substituted proline ester via the aldol reaction with OBO-serine aldehyde, (E)-selective alpha,beta-dehydroamino acid synthesis using a new HWE reagent, and catalytic hydrogenation.
Journal of Insect Physiology | 2011
Toyomi Kotaki; Tetsuro Shinada; Kanako Kaihara; Yasufumi Ohfune; Hideharu Numata
Juvenile hormone III skipped bisepoxide (JHSB(3)), methyl (2R,3S,10R)-2,3;10,11-bisepoxyfarnesoate was recently determined as a novel juvenile hormone (JH) in a stink bug, Plautia stali. To further confirm the biological function of JHSB(3) in this insect, its juvenilizing, reproduction-stimulating and diapause-terminating activities and the presence in the hemolymph were examined. Topical application of JHSB(3) to last instar nymphs inhibited their metamorphosis in a dose-dependent fashion. In allatectomized and diapausing adults, JHSB(3) application exerted stimulatory effects on the development of ovaries and ectadenia in females and males, respectively. JHSB(3) was detected from the hemolymph of reproductively active females by gas chromatography-mass spectrometry analysis while its titer in the hemolymph collected from diapausing adults was too low to be detected. These results demonstrated that JHSB(3) has biological function as a JH in P. stali. Topical application of JHSB(3), its stereoisomers and 10R-JH III also indicated that compounds with the 2R,3S-configuration were more potent than those with the 2S,3R-configuration and 2,3-double bond.
Organic Letters | 2014
Kentaro Oe; Yasufumi Ohfune; Tetsuro Shinada
A short total synthesis of (-)-kainic acid has been developed involving a novel diastereofacial differentiating Cu-catalyzed Michael addition-cyclization reaction, which provided access to a chiral pyrroline in a highly stereoselective manner. The chiral pyrroline was converted to (-)-kainic acid via the stereoselective 1,4-reduction of the pyrroline double bond in three steps.
Tetrahedron Letters | 2003
Masanori Kawasaki; Kosuke Namba; Hidekazu Tsujishima; Tetsuro Shinada; Yasufumi Ohfune
Highly enantioselective synthesis of (2R)-α-(hydroxymethyl)glutamate (1), a selective agonist of mGluR2 and 3, was achieved in short steps using an asymmetric version of the Strecker synthesis. This was converted into its α-methoxymethyl- and α-benzyloxymethyl derivatives 2 and 3, possible ligands as tools to investigate glutamate receptors, via protection of the sterically hindered amino group by means of phase transfer catalyst.
Tetrahedron Letters | 2003
Yasufumi Ohfune; Takashi Demura; Seiji Iwama; Hiromi Matsuda; Kosuke Namba; Keiko Shimamoto; Tetsuro Shinada
Abstract Efficient synthesis of (+)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (LY354740: 1 ) and its structurally related analogs (−)- 2 and (−)- 3 has been accomplished starting with (1 S ,2 R )-1-amino-2-hydroxycyclopentane- or cyclohexanecarboxylic acid ( 4 or 17 ) via an intramolecular cyclopropanation of α-diazo acetamide.
RSC Advances | 2014
Kentaro Maeda; Yu-ichi Kiniwa; Yasufumi Ohfune; Shinichi Ishiguro; Koichi Suzuki; Kazuya Murata; Hideaki Matsuda; Tetsuro Shinada
A new method has been developed for the synthesis of 3-(1-aminoalkyl)-4-hydroxycyclobut-3-ene-1,2-dione [α-amino squaric acid (α-Asq)]-containing peptides using solid phase peptide synthesis according to an Fmoc protecting group strategy. FmocHN-Gly-[α-Asq]-Oi-Pr was successfully used as a coupling unit in this method, which allowed for the construction of α-Asq-containing hexapeptide libraries including Sq-Gly and Sq-Phe units using the Wang-resin. Peptides containing the α-Asq moiety exhibited inhibitory activity towards a digestive enzyme.
Journal of Organic Chemistry | 2006
Trevor K. Ellis; Hisanori Ueki; Takeshi Yamada; Yasufumi Ohfune; Vadim A. Soloshonok
Bulletin of the Chemical Society of Japan | 2003
Yasufumi Ohfune; Tetsuro Shinada