An unexpected four-step reaction sequence was discovered in the course of investigation of the interaction between 3-(furan-2-yl)allylamines and bromomaleic anhydride. This conversion begins with the initial N-acylation of the allylamines by the anhydride, followed by intramolecular Diels–Alder reaction, which is accompanied by a dehydrohalogenation, and ends with the formation of partially unsaturated furo[2,3-f]isoindoles followed by transposition of aromaticity from the furan moiety to the neighboring cyclohexane ring. The reaction between 3-(furan-3-yl)allylamines and bromomaleic anhydride does not stop at a furo[2,3-f]isoindole formation step, but proceeds further with the cleavage of the furan ring in a 100% atom-efficient fashion to provide polysubstituted isoindoline-4-carboxylic acids.

中文翻译：

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在 3-（呋喃基）烯丙胺与溴马来酸酐相互作用期间呋喃异吲哚中芳香性从呋喃到环己烷环的转移

在研究 3-(呋喃-2-基) 烯丙胺和溴马来酸酐之间的相互作用的过程中发现了一个意想不到的四步反应序列。这种转化从烯丙胺被酸酐的初始 N-酰化开始，然后是分子内 Diels-Alder 反应，伴随着脱卤化氢，最后形成部分不饱和的呋喃 [2,3-f] 异吲哚，然后是芳香性从呋喃部分转移到相邻的环己烷环。3-(呋喃-3-基)烯丙胺和溴马来酸酐之间的反应不会在呋喃[2,3-f]异吲哚形成步骤停止，而是进一步进行呋喃环的裂解，原子效率为100%提供多取代的异二氢吲哚-4-羧酸。