In:
Chinese Journal of Chemistry, Wiley, Vol. 37, No. 8 ( 2019-08), p. 827-833
Abstract:
An effective approach relying on a Lewis acid‐ or Brønsted 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 loadings of Ph 3 AuPOTf (≤ 0.5 mol%) in the presence of Ga(OTf) 3 , In(OTf) 3 , or HOTf (~10mol%) as a co‐catalyst, at practical reaction rates as an alternative to the conventional ~10 mol% loadings of the gold(I) catalyst in the glycosylation. Polyphyllin 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 used. By 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.
Type of Medium:
Online Resource
ISSN:
1001-604X
,
1614-7065
DOI:
10.1002/cjoc.201900126
Language:
English
Publisher:
Wiley
Publication Date:
2019
detail.hit.zdb_id:
2144352-X
SSG:
6,25