作者:Joachim Thiem、Sabine Köpper
DOI:10.1016/s0040-4020(01)97588-x
日期:1990.1
the N-iodosuccinimide glycosylation procedure employing regioselectively blocked L-digitoxosides and L-digitoxals. Assumed 13-neighboring group participations were studied in acid- and silver or mercury salt-promoted glycosylations with selectively functionalized digitoxoses or their glycosyl chlorides. No evidence for enhanced β:α-ratios exceeding that of previous glycosylations in 2-deoxy-ribo components
奇异霉素四糖的各种二糖和三糖前体是通过N-碘琥珀酰亚胺化糖基化方法,使用区域选择性封闭的L-数字氧苷和L-数字氧醛制备的。假设研究了13个相邻基团的参与,其中包括酸和银或汞盐促进的糖基化反应,以及选择性官能化的洋地黄糖或其糖基氯化物的糖基化作用。在2-脱氧核糖组分中,没有观察到增强的β:α-比率超过先前糖基化的证据。一种直接的顺序合成方法既应用了研究的糖基化方法,又应用了封闭的D C的合成获得了奇异霉素的BA四糖。通过广泛的1 H NMR光谱确定寡糖的整个结构和构象。