AbstractHere we report a simple and general method to achieve fully unprotected, stereoselective glycosylation of carboxylic acids, employing bench‐stable allyl glycosyl sulfones as donors. Running the glycosylation reaction under basic conditions was crucial for the efficiencies and selectivities. Both the donor activation stage and the glycosidic bond forming stage of the process are compatible with free hydroxyl groups, thereby allowing for the use of fully unprotected glycosyl donors. This transformation is stereoconvergent, occurs under mild and metal‐free conditions at ambient temperature with visible light (455 nm) irradiation, and displays remarkable scope with respect to both reaction partners. Many natural products and commercial drugs, including an acid derived from the complex anticancer agent taxol, were efficiently glycosylated. Experimental studies provide insights into the origin of the stereochemical outcome.
摘要我们在此报告了一种简单而通用的方法,该方法采用台式稳定的烯丙基糖基砜作为给体,实现了
羧酸的完全无保护、立体选择性糖基化。在碱性条件下进行糖基化反应对效率和选择性至关重要。该过程的供体活化阶段和糖苷键形成阶段都与游离羟基兼容,因此可以使用完全无保护的糖基供体。这种转化具有立体转换性,在环境温度和可见光(455 纳米)照射下,在温和、无
金属的条件下进行,而且对两个反应伙伴都有显著的影响。许多
天然产物和商业药物,包括从复合抗癌剂
紫杉醇中提取的一种酸,都被有效地糖基化了。实验研究为了解立体
化学结果的起源提供了见解。