Enantiocontrolled Synthesis of 2,6-Disubstituted Piperidines by Desymmetrization of <i>m</i><i>eso</i>-<i>η</i>-(3,4,5)-Dihydropyridinylmolybdenum Complexes. Application to the Total Synthesis of (−)-Dihydropinidine and (−)-Andrachcinidine
作者:Chutian Shu、Lanny S. Liebeskind
DOI:10.1021/ja029537y
日期:2003.3.1
A conceptually new approach to the enantiocontrolled synthesis of 2,6-disubstituted piperidines was achieved by desymmetrization of meso-2,6-dimethoxy-eta-(3,4,5)-dihydropyridinylmolybdenum complexes. After protection of the piperidine nitrogen as a urethane derived from (+)- or (-)-trans-2-(alpha-cumyl)cyclohexyl (TCC), a sequential, one-pot methoxide abstraction/nucleophilic addition/methoxide a
2,6-二取代哌啶的对映控制合成的概念上新方法是通过meso-2,6-二甲氧基-eta-(3,4,5)-dihydropyridinylmolybdenum 配合物的去对称化实现的。将哌啶氮保护为衍生自 (+)- 或 (-)-trans-2-(α-枯基) 环己基 (TCC) 的氨基甲酸酯后,依次进行一锅甲醇提取/亲核加成/甲醇提取/亲核此外,2,6-二取代-eta-(3,4,5)-二氢吡啶基钼配合物的产率很高。该序列通过高度非对映选择性甲醇盐提取 (>40:1) 进行。高产量的原脱金属和 N-脱保护为各种 2,6-二取代哌啶提供了一种简单且对映控制的合成入口。