Formal Synthesis of <i>Aspidosperma</i> Alkaloids via the Intramolecular [3 + 2] Cycloaddition of 2-Azapentdienyllithiums
作者:William H. Pearson、Aaron Aponick
DOI:10.1021/ol0602506
日期:2006.4.1
[reaction: see text] A formal synthesis of the Aspidosperma alkaloids aspidospermidine, aspidospermine, and quebrachamine is reported through an efficient preparation of Stork's penultimate intermediate. The key step of the sequence involved an intramolecular [3 + 2] cycloaddition of the 2-azapentadienyllithium 21 formed in situ from the corresponding imine 1, which after N-alkylation of the resulting
[反应:见正文]据报道,通过有效制备Stork的倒数第二个中间体,可以合成天冬子碱生物碱,天冬酰胺,天冬酰胺和槲皮胺。该序列的关键步骤涉及由相应的亚胺1在原位形成的2-氮杂戊二烯基锂21的分子内[3 + 2]环加成反应,在将所得环加合物进行N-烷基化后,其收率极高。该合成代表了用于连接必要的吲哚的经典三环酮的新分离。