Institute of Organic Chemistry, Gottfried-Wilhelm-Leibniz University of Hannover, D-30167 Hannover, Germany.
Org Lett. 2012 Oct 5;14(19):4990-3. doi: 10.1021/ol302388t. Epub 2012 Sep 25.
The first enantioselective copper-catalyzed cyclopropanation of N-acyl indoles is described. Using carbohydrate-based bis(oxazoline) ligands (glucoBox), the products were obtained in up to 72% ee. Cyclopropanation of N-Boc 3-methyl indole yielded a product with an all-carbon quaternary stereocenter, which is a valuable building block for the synthesis of indole alkaloids: Deprotection and rearrangement gave a tricyclic hemiaminal ester in 96% ee, which was subsequently employed as a key intermediate for the synthesis of (-)-desoxyeseroline.
首次描述了 N-酰基吲哚的对映选择性铜催化环丙烷化反应。使用基于碳水化合物的双（恶唑啉）配体（glucoBox），可以高达 72%的对映体过量值获得产物。N-Boc 3-甲基吲哚的环丙烷化反应得到了具有全碳季立体中心的产物，这是合成吲哚生物碱的有价值的构建块：脱保护和重排得到了 96%对映体过量值的三环半缩醛酯，随后该化合物被用作（-）-去氧鹅膏碱合成的关键中间体。
