A simple entry to sugar derived bispiropyrrolidines through non-stabilized azomethine ylides
作者:Piyali Deb Barman、Divya Goyal、Upendra Kumar Daravath、Ishita Sanyal、Sukhendu B. Mandal、Asish Kumar Banerjee
DOI:10.1016/j.tetlet.2013.05.027
日期:2013.7
cycloaddition reaction of a carbohydrate-derived exocyclic olefin with in situ generated non-stabilized azomethine ylides, formed by the reaction of sarcosine (a secondary α-amino acid) with isatins, acenaphthenedione and cycloalkanones in refluxing toluene afforded bispiropyrrolidine derivatives in 78–92% yield, when DIPEA was used as a base. However, using Et3N/DBU, the reaction of the olefin precursor
碳水化合物衍生的环烯烃与原位生成的非稳定的偶氮甲亚胺的1,3-偶极环加成反应是由肌氨酸(一种α-氨基酸的二级氨基酸)与靛红,啶二酮和环烷酮在回流的甲苯中反应生成的,得到双螺并吡咯烷衍生物当以DIPEA为基础时,产率为78-92%。但是,使用Et 3 N / DBU,烯烃前体与甲亚胺叶立德的反应(源自环戊酮和肌氨酸的缩合反应)提供了51-53%的收率。另一方面,在没有碱的情况下,环加成产物的收率急剧下降至10-22%。