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Kinetic Resolution of Isoxazolidines by a Pd−BINAP Complex
Author(s) -
Ohta Tetsuo,
Kamizono Hiroyuki,
Kawamoto Aya,
Hori Kazushige,
Furukawa Isao
Publication year - 2002
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200211)2002:22<3855::aid-ejoc3855>3.0.co;2-4
Subject(s) - chemistry , kinetic resolution , carboxylate , substrate (aquarium) , binap , catalysis , substituent , yield (engineering) , palladium , medicinal chemistry , selectivity , stereochemistry , decomposition , enantiomeric excess , enantioselective synthesis , organic chemistry , oceanography , materials science , geology , metallurgy
Asymmetric decomposition of isoxazolidine derivatives under catalysis by optically active palladium( II ) complexes was examined. When racemic ethyl cis ‐2,5‐dimethyl‐5‐phenylisoxazolidine‐3‐carboxylate ( cis ‐ 1a ) was treated with a catalytic amount of [Pd(MeCN) 2 {( S )‐TolBINAP}](BF 4 ) 2 in CH 2 Cl 2 for 60 h, optically active substrate was recovered with 99% ee and in 48% yield. The highest selectivity was achieved on treatment of racemic ethyl trans ‐2,4‐dimethyl‐5,5‐diphenylisoxazolidine‐3‐carboxylate, to give the optically active substrate in 74% yield with 35% ee . The k f / k s value of this reaction reaches as high as 732. For this decomposition, each substrate should have both a methyl group on the 2‐position and an alkoxycarbonyl group on the 3‐position of the isoxazolidine ring. The enantioselectivities of the recovered substrates were influenced not only by the other substituent groups on the 4‐ and 5‐positions but also by the geometrical structures of the substrates. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)