TiCl<sub>4</sub>-Promoted Cyclization Reactions of Aminoacetals and Ethenetricarboxylates Leading to Nitrogen-Containing Heterocycles
作者:Shoko Yamazaki、Masachika Takebayashi
DOI:10.1021/jo201011n
日期:2011.8.5
3-aminopropionaldehyde diethyl acetal (2a) and 1a in the presence of 1 equiv of TiCl4 at room temperature gave 4-ethoxypiperidine-2,3,3-tricarboxylate 3a in 92% yield with a 2,4-diastereomer ratio of 1:1. The reaction in the presence of 3 equiv of TiCl4 gave 2,4-trans-piperidine derivative 3a in 86% yield predominantly. The reaction of aminoacetaldehyde diethyl/dimethyl acetals 2c,d and 1a with 3 equiv
已经研究了路易斯酸催化的氨基缩醛2和三乙基三羧酸三乙酯(1a)的环化。3-氨基丙醛二乙基乙缩醛(2a)与1a在1当量TiCl 4的存在下于室温下反应,以92%的收率得到4-乙氧基哌啶-2,3,3-三羧酸3a,2,4-非对映异构体比率1:1 在3当量的TiCl 4的存在下反应,主要以86%的产率得到2,4-反式-哌啶衍生物3a。氨基乙醛二乙基/二甲基缩醛2c,d和1a的反应用3当量的TiCl 4产生2,4-反-4-吡咯烷-2,3,3-三羧酸盐5a,b。