O
Osamu Yonemitsu
Researcher at Hokkaido University
Publications - 193
Citations - 3598
Osamu Yonemitsu is an academic researcher from Hokkaido University. The author has contributed to research in topics: Total synthesis & Polyketide. The author has an hindex of 28, co-authored 193 publications receiving 3522 citations.
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Journal ArticleDOI
Specific removal of o-methoxybenzyl protection by DDQ oxidation.
TL;DR: Methoxybenzyl protecting groups of alcohols were readily and efficiently removed with DDQ in CH2Cl2-H2O at room temperature under these neutral conditions, other usual protecting groups, isopropylidene, methoxymethyl, benzyloxymmethyl, tetrahydropyranyl, acetyl, t-butyldimethylsilyl, benyl, benzoyl, and tosyl, as well as functional groups, epoxide, double bond, and ketone, were remained unchanged as discussed by the authors.
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On the selectivity of deprotection of benzyl, mpm (4-methoxybenzyl) and dmpm (3,4-dimethoxybenzyl) protecting groups for hydroxy functions
TL;DR: In this paper, the 4-methoxybenzyl (MPM) protecting group for hydroxy functions is readily removed with DDQ in dichloromethane containing a small amount of water at room temperature.
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MPM (4-methoxybenzyl) protection of hydroxy functions under mild acidic conditions
TL;DR: In this paper, a mild protection method for hydroxy functions with a MPM (4methoxybenzyl) group, various types of hydroxy compounds were treated with MPM trichloroacetimidate in the presence of an acid catalyst.
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Protection of hydroxy groups by intramolecular oxidative formation of methoxybenzylidene acetals with DDQ
TL;DR: On DDQ under anhydrous conditions, hydroxy groups located at α or β position to methoxybenzyl ether groups were readily protected by the intramolecular oxidative formation of acid-sensitive methoxy benzylidene acetals, which were further oxidized to alkali-sensitive hydroxy esters in the presence of H 2 O as mentioned in this paper.
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Synthesis of erythronolide a via a very efficient macrolactonization under usual acylation conditions with the Yamaguchi reagent
TL;DR: Macrolactonization of 3,5- O -(3,4-dimethoxybenzylidene)-9,11-O -(2,4,6-trimethylbenzo-idene)(9 S )-9-dihydroerythronolide A seco-acid (4 ) was reexamined under various conditions and found to proceed rapidly only by treatment of 4 with Yamaguchi's reagent, 2.4, 6-trichlorobenzoyl chloride, in the presence