Synthesis of Spirostanol Saponins via Gold(Ⅰ)-Catalyzed Glycosylation in the Presence of Ga(Otf)3, In(Otf)3, or HOTf

作     者：Teddy Stephen Ehianeta Dacheng Shen Peng Xu Biao Yu 

作者机构：State Key Laboratory of Bio-organic and Natural Products ChemistryCenter for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of Sciencesand University of Chinese Academy of Sciences345 Lingling RoadShanghai 200032China 

出 版 物：《Chinese Journal of Chemistry》 (中国化学（英文版）)

年 卷 期：2019年第37卷第8期

页      面：827-833页

核心收录：

学科分类：080904[工学-电磁场与微波技术] 0810[工学-信息与通信工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080402[工学-测试计量技术及仪器] 0804[工学-仪器科学与技术] 081001[工学-通信与信息系统] 

基　　金：the National Natural Science Foundation of China (Nos.21432012,21621002 and 21602240) Strategic Priority Research Program of CAS (No.XDB20020000) 

主　　题：Presence via practical presence catalyst mol was has 

摘      要：Summary of main observation and conclusion An effective approach relying on a Lewis acid-or Brφnsted acid-assisted gold(Ⅰ)-catalyzed glycosylation has been reported in the synthesis of a panel of the representative natural spirostanol saponins,namely polyphyllin D (1),polyphyllin V (2),dioscin (3),formosanin C (4),and a derivative of polyphyllin D bearing a terminal azide group (5).This approach highlights the engagement of low Ioadings of Ph3AuPOTf (≤ 0.5mol%) in the presence of Ga(OTf)3,In(OTf)3,or HOTf (~10 mol%) as a co-catalyst,at practical reaction rates as an alternative to the conventional ~10 mol%Ioadings of the gold(Ⅰ) catalyst in the *** D (1) was obtained in 41% overall yield over six steps compared to the maximum 30% yield in previous syntheses,where conventional donors and promoters were *** exploiting a regioselective rhamnosylation,a one-pot approach was adopted to assemble 1 and 5,thus further strengthening the efficiency of the gold(Ⅰ)-catalyzed glycosylation.