TiCl4 促进的氨基缩醛和亚乙基三羧酸酯的环化反应生成含氮杂环。

TiCl4-promoted cyclization reactions of aminoacetals and ethenetricarboxylates leading to nitrogen-containing heterocycles.

机构信息

Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan.

出版信息

J Org Chem. 2011 Aug 5;76(15):6432-7. doi: 10.1021/jo201011n. Epub 2011 Jul 8.

DOI:10.1021/jo201011n

Abstract

Lewis acid-catalyzed cyclization of aminoacetals 2 and triethyl ethenetricarboxylate (1a) has been examined. The reaction of 3-aminopropionaldehyde diethyl acetal (2a) and 1a in the presence of 1 equiv of TiCl(4) 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 TiCl(4) 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 of TiCl(4) gave 2,4-trans-4-pyrrolidine-2,3,3-tricarboxylates 5a,b predominantly.

摘要

研究了路易斯酸催化的氨基缩醛 2 和三乙基乙二羧酸酯（1a）的环化反应。在室温下，3-氨基丙醛二乙酯（2a）和 1a 在 1 当量 TiCl(4)的存在下反应，以 92%的收率得到 4-乙氧基哌啶-2,3,3-三羧酸酯 3a，其 2,4-非对映异构体比例为 1:1。在 3 当量 TiCl(4)的存在下，主要得到 2,4-反式-哌啶衍生物 3a，收率为 86%。氨基乙醛二乙酯/二甲缩醛 2c、d 和 1a 与 3 当量 TiCl(4)反应，主要得到 2,4-反式-4-吡咯烷-2,3,3-三羧酸酯 5a、b。