Enantiopure 2,6-disubstituted piperidines bearing one alkene- or alkyne-containing substituent: preparation and application to total syntheses of indolizidine-alkaloids
作者:Hui Liu、Deyong Su、Guolin Cheng、Jimin Xu、Xinyan Wang、Yuefei Hu
DOI:10.1039/b927007h
日期:——
general and efficient procedure for the preparation of 2,6-disubstituted piperidines bearing one alkene- or alkyne-containing substituent was developed by using non-racemic Betti base as a chiral auxiliary. Many chiral benzylamines are excellent auxiliaries, but they were rarely used for this purpose because of the inefficient removal of the N-benzyl auxiliary residue under non-hydrogenative conditions
通过使用非外消旋的Betti碱作为手性助剂,开发了一种制备带有一个含烯烃或炔烃取代基的2,6-二取代哌啶的通用有效方法。许多手性苄胺是极好的助剂,但由于在非氢化条件下不能有效去除N-苄基辅助残基,因此很少用于此目的。我们发现ñ,ñ-二取代的贝蒂碱衍生物具有典型的曼尼希结构 邻萘酚。当它进行碱催化的生成时邻醌甲基化物,实现了有效的非氢化N-脱苄基作用,并且烯烃和炔烃基团得以幸存。为了证明该方法的有效性和产品的多功能性,采用了不对称的总合成方法吲哚嗪-生物碱 (-)-167B, (-)-195小时, (-)-209D 和 (-)-223AB 完成了。