The First Bidirectional [4+2] Cycloadditions of Benzo[1,2:4,5]dicyclobutenes: Synthesis of Benzo[1,2-<i>f</i>:4,5-<i>f′</i>]diisoindole-1,3,7,9-tetraones
作者:Ismail Abdelshafy Abdelhamid、Holger Butenschön
DOI:10.1002/ejoc.201403247
日期:2015.1
respective bidirectional reactions have barely been explored. Here, the first bidirectional cycloadditions starting from benzo[1,2:4,5]dicyclobutene derivatives are presented using N-methylmaleinimide as the dienophile. The benzo[1,2:4,5]dicyclobutene derivatives used have in common that they are dimethylacetals of the respective diones. As a consequence, the cycloadducts easily undergo elimination of methanol
双向反应是合成更大的、通常对称的化合物的有效工具。虽然苯并环丁烯衍生物的开环以及随后形成的邻醌二甲烷的环加成已被广泛用于合成各类化合物,例如类固醇、并苯、天然以及合成低聚环,包括杂环系统,但各自的双向反应具有几乎没有被探索过。在这里,第一个从苯并[1,2:4,5]二环丁烯衍生物开始的双向环加成是使用N-甲基马来酰亚胺作为亲二烯体的。所用的苯并[1,2:4,5]二环丁烯衍生物的共同点是它们是各自二酮的二甲基缩醛。因此,环加合物很容易消除甲醇。