Total Synthesis of (2Z)-[(4R,5R,6S)-6-(β-D-Glucopyranosyloxy)-4,5-dihydroxycyclohex-2-en-1-ylidene]ethanenitrile, a Cyanoglucoside fromIlex warburgii
作者:Delphine Josien-Lefebvre、Claude Le Drian
DOI:10.1002/hlca.200790015
日期:2007.1
The total synthesis of the noncyanogenic cyanoglucoside 1, originally isolated from Ilex warburgii, was achieved in nine steps (9% overall yield), starting from an optically pure Diels–Alder adduct ((+)-3). The key step of the synthesis, the glycosidation, was carried out under Koenigs–Knorr conditions closely related to those developed for the total syntheses of (−)-lithospermoside and (−)-bauhinin
从光学纯的Diels–Alder加合物((+)- 3)开始,九个步骤(总收率为9%)实现了最初从华氏冬青属植物中分离出来的非氰基氰基葡萄糖苷1的总合成。合成的关键步骤,糖基化,是在Koenigs-Knorr条件下进行的,该条件与为(-)-紫草精苷和(-)-紫胶苷的总合成开发的条件紧密相关。我们必须调节用于糖苷配基的两个自由的顺式构型的OH基的保护基,其以非常好的收率(62%)提供了所需的β -d-葡糖苷中间体15。