Synthesis of Verbascoside: A Dihydroxyphenylethyl Glycoside with Diverse Bioactivity
作者:Howard I. Duynstee、Martijn C. de Koning、Huib Ovaa、Gijs A. van der Marel、Jacques H. van Boom
DOI:10.1002/(sici)1099-0690(199910)1999:10<2623::aid-ejoc2623>3.0.co;2-k
日期:1999.10
approach to trichloroacetimidate 8c commenced with the iodonium ion mediated glycosidation of ethyl 2,3,4-tri-O-benzoyl-1-thio-α-L-rhamnopyranside (15) with 1,2:5,6-diisopropylidene-D-glucofuranose (16) to afford disaccharide 17, which was transformed into 8c in five steps. Condensation of 8a–c with 2-[3,4-di-(tert-butyldimethyl-silyloxy)phenyl]ethanol (12) gave, after deacylation, key intermediate
TMSOTf 介导的 4,6-O-苯亚甲基-1-硫代-β-D-吡喃葡萄糖苷 (2) 与过乙酰化 α-L-吡喃鼠李糖基三氯乙酰亚胺供体 3a 的缩合导致原酸酯 4 的形成,其在乙酰化后重排转化为乙基 3-O-(α-L-吡喃鼠李糖基)-1-硫代-β-D-吡喃葡萄糖苷衍生物 6a。后一种化合物被转化为相应的三氯乙酰亚胺供体 8a-b。三氯乙酰亚胺酯 8c 的另一种方法开始于碘鎓离子介导的 2,3,4-三-O-苯甲酰基-1-硫代-α-L-鼠李糖苷 (15) 与 1,2:5,6-二异亚丙基- D-呋喃葡萄糖 (16) 得到二糖 17,分五步将其转化为 8c。8a–c 与 2-[3,4-二-(叔丁基二甲基-甲硅烷氧基)苯基]乙醇 (12) 缩合,脱酰后得到关键中间体 14。