Lewis Acids as Mild and Effective Catalysts for the Synthesis of 3,5-Bis[(hetero)arylidene]piperidin-4-ones
作者:Evgeniya Leonova、Mihail Makarov、Zinaida Klemenkova、Irina Odinets
DOI:10.1002/hlca.201000005
日期:2010.10
with (hetero)aromatic aldehydes promoted by Lewis acids or bases were examined. This comparative study has revealed three effective catalytic systems based on Lewis acids, i.e., LiClO4 and MgBr2 (in the presence of tertiary amine), and BF3⋅Et2O, for the synthesis of N‐alkyl‐substituted 3,5‐bis(heteroarylidene)piperidin‐4‐ones, including those bearing acid‐ or base‐labile groups both in the (hetero)aromatic
考察了路易斯酸或碱促进的N-烷基和N H-哌啶-4-酮衍生物与(杂)芳族醛的醛-丁烯醛缩合反应。这个比较研究显示基于三个有效的催化系统的路易斯酸,即,的LiClO 4和MgBr 2(在叔胺的存在下),和BF 3 ⋅Et 2 O,用于合成Ñ烷基取代的3,5-双(杂亚芳基)哌啶-4-酮,包括在(杂)芳族基团和N-原子的烷基取代基中均带有酸或碱不稳定基团的那些。对于LiClO 4介导的合成,观察到最高的反应速率。既MgBr 2 -和的LiClO 4种介导的合成是低效的情况下Ñ H-哌啶-4-酮,而BF 3 ⋅Et 2 ö提供以高产率最终化合物。该催化剂特别有利,因为在O保护的哌啶-4-酮的情况下,它可以同时缩合和脱保护。