Highly diastereoselective annulation of 2-substituted 3-nitro-2<i>H</i>-chromenes with hemicurcuminoids and curcuminoids <i>via</i> a double and triple Michael reaction cascade
作者:Nikolay S. Zimnitskiy、Alexey Yu. Barkov、Ivan A. Kochnev、Igor B. Kutyashev、Vladislav Yu. Korotaev、Vyacheslav Ya. Sosnovskikh
DOI:10.1039/d2nj02019j
日期:——
72 h in the presence of Cs2CO3 proceeds by way of a triple Michael/Michael/oxa-Michael cascade leading to 3,6-diaryl-6a-nitro-2,3,5,6a,7,12b-hexahydro-1H,6H-chromeno[6,5-c]chromen-1-ones in 71–97% yields. 2-Phenyl-2-(trifluoromethyl)-3-nitro-2H-chromenes under the analogous conditions react with enediones to form 2-(2-phenyl-2-(trifluoromethyl)-2H-chromen-4-yl)-1,5-diarylpent-4-ene-1,3-diones as a result
K 2 CO 3催化的 ( E )-1,5-二芳基-和 1-烷基-5-芳基戊-4-烯-1,3-二酮与 2-三氟甲基-和 2-苯基-取代的双迈克尔加成3-nitro-2 H -chromenes 在二氯甲烷中在室温下放置 48 小时,生成 10-aroyl(acyl)-7-aryl-6a-nitro-6,6a,7,8,10,10a-hexahydro-9 H -苯并[ c ]chromen-9-ones 以 75–98% 的产率作为单独的非对映异构体在 C-6、C-6a 和 C-7 原子和 H-9b 原子上相对于稠合三环体系具有顺式排列的取代基. 在 Cs 2 CO 3存在下,类姜黄素在氯仿中回流 72 小时的类似立体选择性过程通过三重 Michael/Michael/oxa-Michael 级联产生 3,6-diaryl-6a-nitro-2,3,5,6a,7,12b-hexahydro-1