Michinori Karikomi
Utsunomiya University
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Featured researches published by Michinori Karikomi.
Tetrahedron Letters | 2003
Yasushi Ogawa; Masahito Toyama; Michinori Karikomi; Katsura Seki; Kazuo Haga; Tadao Uyehara
Abstract Both enantiomers of ( P )-(+)-2- and ( M )-(−)-2-acetoxy-11,14-dimethyl[5]helicenes 8 were synthesized by asymmetric aromatic oxy-Cope rearrangement of the corresponding chiral bridged bicyclic compounds, which were obtained by enzymatic resolution. The absolute configurations of 8 were assigned by their circular dichroism spectra.
Tetrahedron Letters | 2002
Yasushi Ogawa; Tetsuya Ueno; Michinori Karikomi; Katsura Seki; Kazuo Haga; Tadao Uyehara
Abstract Synthesis of 2-acetoxy[5]helicene has been achieved by sequential double aromatic oxy-Cope rearrangement strategy. Combination of 1-methoxybicyclo[2.2.2]oct-5-en-2-one and p -bromophenylmagnesium bromide gave 3-bromophenanthrene through several steps including an aromatic oxy-Cope rearrangement as a key step. The second oxy-Cope rearrangement and the following transformation gave 2-acetoxy[5]helicene by similar procedure.
Tetrahedron Letters | 2002
Michinori Karikomi; Shigeru Watanabe; Yukino Kimura; Tadao Uyehara
Abstract A novel synthetic method for several tetrahydrofuran derivatives by intramolecular cyclization of epoxyalcohols is described. The presence of a catalytic amount of magnesium halide altered the regio- and stereoselectivity of the cyclization reaction.
Tetrahedron Letters | 1997
Michinori Karikomi; Kouji Arai; Takashi Toda
Abstract A novel stereoselective synthesis of 3-hydroxyazetidines starting from 2,3-epoxyamines is described. Regioselectivity of the intramolecular cyclization of 2,3-epoxyamines is controlled by the use of magnesium bromide. The cyclization proceeds with retention of the stereochemistry, caused by double inversion of two sequential S N 2 reactions of the epoxyamines.
Heterocycles | 1992
Takashi Toda; Michinori Karikomi; Masabumi Ohshima; Masaaki Yoshida
Several (R * ,S * )-1-alkyl-3-hydroxy-2-phenylazetidines (1) were synthesized by the reaction of (R * ,R * )-2-(1-bromobenzyl)oxirane (2a) with aliphatic primary amines in good yields. By the reaction of (R * ,S * )-2-(1-bromobenzyl)oxirane (2b), only (R * ,R * )-2-aminomethyl-3-phenyloxirane (3) was obtained. Also, the reaction of (R * ,R * )-2-(1-bromobenzyl)-2-methyloxirane (2c) gave a mixture of (R * ,S * )-3-hydroxy-3-methyl-2-phenylazetidine (4) as the major product and (R * ,S * )-2-aminomethyl-2-methyl-3-phenyloxirane (5) as the minor product
Chemical Communications | 2006
Naohiro Kameta; Yoshinobu Nagawa; Michinori Karikomi; Kazuhisa Hiratani
A racemic [2]rotaxane, composed of an asymmetric rotor and an asymmetric axle, formed a diastereomer with an amino acid derivative, and showed an optical response for the chiral recognition.
Chemical Communications | 2004
Kazuhisa Hiratani; Nobuko Sakamoto; Naohiro Kameta; Michinori Karikomi; Yoshinobu Nagawa
A 25 membered crownophane with two hydroxy and two amide groups around the cavity has been reported for the first time to be able to include carbonic acid formed from both carbon dioxide and water molecules to give a stable 1:1 complex at room temperature.
Tetrahedron Letters | 2001
Tadao Uyehara; Kayoko Onda; Naoko Nozaki; Michinori Karikomi; Masako Ueno; Toshio Sato
The racemic mixture of 2-thiocyanatoneopupukeanane, a marine sesquiterpene-thiocyanate with a tricylo[4.3.1.03,7]decane skeleton, was prepared through a pinacol-type rearrangement of a bicyclo[2.2.2]oct-5-en-2-ol giving a bicyclo[3.2.1]oct-6-en-2-one derivative and an aldol reaction leading to the neopupukeanane framework.
Tetrahedron Letters | 2002
Hiroki Hashimoto; Toshihiro Jin; Michinori Karikomi; Katsura Seki; Kazuo Haga; Tadao Uyehara
An efficient one-pot synthesis of a 10,10-ethylenebicyclo[5.2.1]dec-8-en-4-one derivative, which can be considered as a synthetic intermediate for the taxane skeleton, has been achieved by tandem anionic [1,3] and oxy-Cope rearrangements of 2-vinylbicyclo[3.2.1] oct-6-en-2-ol.
Tetrahedron Letters | 2002
Hiroki Hashimoto; Yasuhiko Abe; Yasuyoshi Mayuzumi; Michinori Karikomi; Katsura Seki; Kazuo Haga; Tadao Uyehara
Abstract The synthesis of unique diquinanes, possessing four continuous methyl groups on the convex of the diquinane skeleton, has been achieved by employing a combination of pinacol-type rearrangement and efficient anionic [1,3] rearrangement strategies.