Synthesis of Calystegine A<sub>3</sub>from Glucose by the Use of Ring-Closing Metathesis
作者:Rune Nygaard Monrad、Charlotte Bressen Pipper、Robert Madsen
DOI:10.1002/ejoc.200900310
日期:2009.7
seven-membered carbon skeleton in calystegine A3 by ring-closing olefin metathesis. Subsequent deoxygenation by the Barton–McCombie protocol, hydroboration and oxidative workup followed by hydrogenolysis affords calystegine A3. The synthesis uses a total of 13 steps from glucose and confirms the absolute configuration of the natural product.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany,
描述了从 D-葡萄糖合成去甲托烷生物碱 calystegine A3。关键步骤采用锌介导的串联反应,其中苄基保护的甲基 6-碘糖苷被裂解成不饱和醛,然后将其转化为相应的苄亚胺并在同一个锅中烯丙基化。通过闭环烯烃复分解,由此获得的官能化的九-1,8-二烯被转化为calystegine A3中的七元碳骨架。随后通过 Barton-McCombie 方案进行脱氧、硼氢化和氧化后处理,然后氢解得到 calystegine A3。该合成总共使用了 13 个葡萄糖步骤,并确认了天然产物的绝对构型。 (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)