Mannich‐type Reactions of Cyclic Nitrones: Effective Methods for the Enantioselective Synthesis of Piperidine‐containing Alkaloids
作者:Vladislav G. Lisnyak、Tessa Lynch‐Colameta、Scott A. Snyder
DOI:10.1002/anie.201809799
日期:2018.11.12
dozens of biologically active 2-substituted and 2,6-disubstituted piperidines, only a limited number of approaches exist for their synthesis. Herein is described two Mannich-type additions to nitrones, one using β-ketoacids under catalyst-free conditions and another using methyl ketones in the presence of chiral thioureas, which can generate a broad array of such 2-substituted materials, as well as other
尽管有数十种具有生物活性的2取代和2,6-二取代的哌啶,但仅存在数量有限的合成方法。本文描述了对硝酮的两种曼尼希型加成反应,一种在无催化剂条件下使用β-酮酸,另一种在手性硫脲存在下使用甲基酮,可以生成大量此类2-取代的物质,以及其他β-N-羟基-氨基酮形式的环变体。两种方法都有广泛的应用范围,后者提供的产品具有高对映选择性(最高98%)。这些方法的结合以及其他关键步骤,使2,6-二取代哌啶生物碱(-)-小叶碱和(-)-sedinone的8步总合成成为可能。