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Synthesis of chiral hydroxythiolanes as potential catalysts for asymmetric organozinc additions to carbonyl compounds

✍ Scribed by Piotr Kiełbasiński; Małgorzata Albrycht; Marian Mikołajczyk; Michał W. Wieczorek; Wiesław R. Majzner; Agnieszka Filipczak; Piotr Ciołkiewicz


Publisher
John Wiley and Sons
Year
2005
Tongue
English
Weight
168 KB
Volume
16
Category
Article
ISSN
1042-7163

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✦ Synopsis


Abstract

Optically active 3‐hydroxythiolane was stereospecifically synthesized from L‐aspartic acid and oxidized to give both diastereomeric S‐oxides, which were chromatographically separated and their configuration was determined. Starting from natural (+)‐(R,R)‐tartaric acid, C~2~‐symmetric trans‐(R,R)‐3,4‐dihydroxythiolane was stereospecifically synthesized for the first time. Some of its monofunctionalized derivatives as well as its S‐oxide were also obtained and characterized. mesocis‐3,4‐Dihydroxythiolane was obtained in a similar way from meso‐tartaric acid and subjected to desymmetrization either by a lipase‐promoted acetylation or hydrolysis of the corresponding O,O'‐diacetyl derivative, to give a chiral monoacetate with ee up to 36%. After its oxidation two diastereomeric sulfoxides were obtained which were separated by chromatography. The crystalline one was subjected to X‐ray analysis and its absolute configuration was determined as 1__S__, 3__S__, 4__R__. All the optically active products were checked as potential catalysts for asymmetric addition of diethylzinc to benzaldehyde. However, they proved to have a very low catalytic activity: yields of the products were in the range 10–90% but ee only up to 10%. A conclusion was drawn that in this type of reaction neither is the hydroxy sulfide (sulfoxide) moiety capable of properly binding diethylzinc, nor does the sulfinyl group exert its normal stereoinduction. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:93–222, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20076


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