A study on the stereoselectivity of C,O bond formation in esterification of cyclic thiohydroxamic acids

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• 作者：Jens Hartung ; Irina Kempter ; Thomas Gottwald ; Michaela Schwarz ; Rainer Kneuer
• 刊名：Tetrahedron: Asymmetry
• 出版年：2009
• 出版时间：23 September 2009
• 年：2009
• 卷：20
• 期：18
• 页码：2097-2104
• 全文大小：785 K

文摘

Esterification of cyclic thiohydroxamic acids, for example, N-hydroxypyridine-2(1H)-thione, N-hydroxy-4-methylthiazole-2(3H)-thione, and N-hydroxy-4-(p-chlorophenyl)-thiazole-2(3H)-thione, occurred with inversion of configuration at the attacked stereocenter, as evident from the use of chiral alcohols, alkyl p-toluene sulfonates, and cyclic sulfates. Stereochemical analysis of enantiomerically pure O-alkyl thiohydroxamates was performed on the basis of CD-spectroscopy and chemical derivatization. The assignment of the relative configuration in cyclic O-esters was feasible via NMR spectroscopy, whereas chiral aliphatic glycolato monoesters required hydroxyl group derivatization with chloro-(4R,5R)-bis[(1R,2S,5R)-menth-1-yloxycarbonyl)]-1,3,2-dioxaphospholane for this purpose.