Anthra[2,3-c]furan, a higher aromatic homologue of isobenzofuran, has been predicted to be a highly reactive polyene lacking any significant aromatic character despite being a 14 Ï-electron system. We have generated this previously inaccessible molecule by acid-catalyzed elimination of methanol from an acetal precursor, and have trapped it with several dienophiles. The overall reaction sequence describes an aromatic-ring homologenation of naphtho[2,3-c]furan to anthra[2,3-c]furan.
蒽并[2,3-c]
呋喃是
异苯并呋喃的高芳香族同系物,尽管它是一个 14 Ï 电子系统,但根据预测,它是一种高活性多烯化合物,缺乏明显的芳香特征。我们通过酸催化消除
缩醛前体中的
甲醇,生成了这种以前无法获得的分子,并用几种二烯烃将其困住。整个反应序列描述了从
萘并[2,3-c]
呋喃到
蒽并[2,3-c]
呋喃的芳环同源反应。