The acid-catalyzed tautomerization of 3-O-substituted kryptogenin 2 was studied, and the effects of acids such as silica gel, TMSOTf, acetic acid, and CDCl3, are discussed. Additionally, a Zn/KI/HOAc reduction based on this tautomerization was adopted, which afforded 2 directly, and provided a facile procedure for the synthesis of methyl protodioscin and other furostanol saponins in a mild way.
研究了酸催化的3-O取代的克里托吉宁(kryptogenin)2的互变异构化,并讨论了
硅胶、三甲基甲
硅烷基
三氟甲磺酸酯(TMSOTf)、
乙酸和
氘氯仿等酸的影响。此外,基于这种互变异构化,采用了Zn/KI/HOAc还原法,直接得到2,并提供了一种温和的方法来合成
甲基原薯蓣皂苷和其他呋甾
皂苷。