An Approach for Determining the Absolute Configuration of C-2 in 2-Oxygenated Phenylethanoid Glycosides by 1H NMR Spectroscopy

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• 作者：Si-Yuan Shao ; Fan Zhang ; Ya-Nan Yang ; Zi-Ming Feng ; Jian-Shuang Jiang ; Pei-Cheng Zhang
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：August 19, 2016
• 年：2016
• 卷：18
• 期：16
• 页码：4084-4087
• 全文大小：399K
• 年卷期：0
• ISSN：1523-7052

文摘

The absolute configurations of 2-oxygenated phenylethanoid glycosides were conveniently determined by ¹H NMR spectroscopy. A comparison of the chemical shift differences (Δδ) of the diastereotopic methylene protons (H-1) demonstrate that a large chemical shift difference corresponds to an R configuration and a small chemical shift difference indicates S for the 2-alkoxy form. However, the situation is contrary to that of the 2-hydroxy form. Furthermore, the mechanism underlying this result is discussed based on the visualized conformations of such compounds.