Synthesis of - and -Glycosyl Isothiocyanates via

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• 作者：Jos&eacute ; L. Jim&eacute ; nez Blanco ; Balla Sylla ; Carmen Ortiz Mellet ; Jos&eacute ; M. Garcí ; a Ferná ; ndez
• 刊名：Journal of Organic Chemistry
• 出版年：2007
• 出版时间：June 8, 2007
• 年：2007
• 卷：72
• 期：12
• 页码：4547 - 4550
• 全文大小：112K
• 年卷期：v.72,no.12(June 8, 2007)
• ISSN：1520-6904

文摘

A practical synthesis of acylated glycosyl isothiocyanates fromsugar oxazolines, by reaction with thiophosgene, is reported.In the absence of any additive, the reaction is governed bythe reverse anomeric effect, leading to the equatoriallyoriented isothiocyanate. However, in the presence of copper(II) chloride, the reaction proceeds preferentially withretention of the configuration at the anomeric center,providing the axial anomer as the major product. Noteworthy,this strategy allows accessing per-O-acetylated glycopyranosyl isothiocyanates with 1,2-cis relative configuration (e.g.,the -anomer in the D-gluco and D-galacto series), a problemthat was outside the scope of previous methodologies.