用浓溶液处理2-(1-羟烷基)丙-2-烯酸甲酯1。用HBr溶液得到(Z)-2-(溴甲基)烷-2-烯酸甲酯2,将其区域选择性地转化成N-取代的甲基(E)-2-(氨甲基)烷-2-烯酸酯3(S N 2反应)并进入ñ取代的甲基2-(1-氨基烷基)丙-2- enoates 4(S ñ 2'反应)。胺对亲核性攻击的区域控制仅通过选择溶剂即可完成,S N 2反应发生在MeCN和S N中。在石油醚中进行2'反应。水解和内酰胺化分别得到β-内酰胺7和8,分别在C(3)处含有外环亚烷基和亚甲基。
addition of 1H-indole/pyrrole-2-carboxylic acids with Morita–Baylis–Hillman-derived allylamines. The readily available starting materials, good stereoselectivity, and gram-scale synthesis make this method valuable for the construction of highly substituted fused heterocycles containing the 1,4-diazepanone moiety.
Stereoselective Synthesis of 3-Carboxy-4,5-dihydropyrroles via an Intramolecular Iminium Ion Cyclization Reaction
作者:Jinbao Xiang、Hongxiang Xie、Zhuo Li、Qun Dang、Xu Bai
DOI:10.1021/acs.orglett.5b01787
日期:2015.8.7
An efficient and practical method has been developed for the synthesis of trans-4,5-disubstituted 3-carboxy-4,5-dihydropyrroles via an intramolecular iminiumion cyclization reaction of readily accessible Baylis–Hillman derivatives and aldehydes in moderate to high yield. These new dihydropyrroles could be easily converted to pyrroles or pyrrolidines.