An exquisite metal-free cascade cyclization reaction of 2-acylbenzoic acids with amines was developed, which provided a powerful method for the one-pot synthesis of diverse isoindoloisoquinoline and benzoindolizinoindole derivatives. This protocol avoided the use of metal catalysts, proceeded with high efficiency and had broad substrate scope. These resulting products could be transformed into tertiary amines under the reduction of LiAlH₄/AlCl₃, followed by the Hofmann elimination offering lots of nitrogen-containing nine-membered ring compounds in excellent yields. All synthesized products containing fused N-polycyclic skeletons were difficult to be constructed using traditional methods and they have a wide range of applications in the pharmaceutical area.

中文翻译：

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从无金属级联环化反应中获得的各种特权 N-多环骨架

开发了一种精细的 2-酰基苯甲酸与胺的无金属级联环化反应，为一锅法合成多种异吲哚异喹啉和苯并吲哚嗪吲哚衍生物提供了强有力的方法。该协议避免使用金属催化剂，效率高，底物范围广。_{这些所得产物可以在LiAlH 4} /AlCl ₃的还原下转化为叔胺，然后进行霍夫曼消除，以优异的收率提供大量含氮九元环化合物。所有含有稠合N-多环骨架的合成产物都很难用传统方法构建，它们在制药领域有着广泛的应用。