对4-羟基香豆素与(E)-3-芳基-2-硝基丙-2-烯醇的反应有显着的溶剂作用:轻松合成高度取代的呋喃/吡喃并[3,2- c ]苯二甲基†
摘要:
在水和DMSO介质中,已观察到对4-羟基香豆素衍生物与(E)-3-芳基/杂芳基-2-硝基丙-2-烯醇的反应具有显着的溶剂作用。该结果用于新型官能化的呋喃/吡喃并[3,2- c ]色烯的直接合成,产率为63-93%,非对映异构体比例最高为≤99:1。此外,该方法简单,温和,高效且无催化剂一锅法可能会为香豆素核上的呋喃/吡喃环的成环提供另一种合成策略。此外,水对该反应的速率和选择性(产物)显示出显着的积极作用。
Chiral squaramide-catalyzed asymmetric synthesis of pyranones and pyranonaphthoquinones via cascade reactions of 1,3-dicarbonyls with Morita–Baylis–Hillman acetates of nitroalkenes
作者:Divya K. Nair、Rubem F. S. Menna-Barreto、Eufrânio N. da Silva Júnior、Shaikh M. Mobin、Irishi N. N. Namboothiri
DOI:10.1039/c4cc02279c
日期:——
Cascade reactions of 1,3-dicarbonyls with Morita-Baylis-Hillman acetates of nitroalkenes using a quinine derived chiral squaramide organocatalyst led to the formation of pyranones and pyranonaphthoquinones in good to excellent yields and high diastereo- and enantioselectivities. Representative examples of the reaction scale-up with a much lower catalyst loading without an appreciable loss of selectivities