硫族元素
甘氨酸
化学
糖基化
失真(音乐)
立体化学
生物化学
有机化学
计算机科学
计算机网络
催化作用
立体选择性
放大器
带宽(计算)
作者
Hao Guo,Jan-Lukas Kirchhoff,Carsten Strohmann,Bastian Grabe,Charles C. J. Loh
标识
DOI:10.1002/anie.202316667
摘要
Abstract Harnessing unconventional noncovalent interactions (NCIs) is emerging as a formidable synthetic approach in difficult‐to‐access glycosidic chemical space. C ‐Glycosylation, in particular, has gained a flurry of recent attention. However, most reported methods are restricted to the relatively facile access to α‐ C ‐glycosides. Herein, we disclose a β‐stereoselective glycosylation of indoles by employing a phosphonoselenide catalyst. The robustness of this protocol is exemplified by its amenability for reaction at both the indolyl C ‐ and N ‐ reactivity sites. In contrast to previous reports, in which the chalcogens were solely involved in Lewis acidic activation, our mechanistic investigation unraveled that the often neglected flanking aromatic substituents of phosphonoselenides can substantially contribute to catalysis by engaging in π‐interactions. Computations and NMR spectroscopy indicated that the chalcogenic and aromatic components of the catalyst can be collectively exploited to foster conformational distortion of the glycal away from the usual half‐chair to the boat conformation, which liberates the convex β‐face for nucleophilic attack.
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