A highly regio-, chemo- and stereoselective divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles is herein described, starting from 2-formylpyrrole and employing Diels–Alder and Heck arylation reactions. 3-(N-Benzyl-2-pyrrolyl)acrylates and 4-(pyrrol-2-yl)butenones underwent a highly endo-Diels–Alder cycloaddition with maleimides to furnish octahydropyrrolo[3,4-e]indoles, which served as precursors in the regioselective synthesis of aza-polycyclic skeletons via an intramolecular Heck arylation reaction. Through the latter reaction, the 3-(N-benzyl-2-pyrrolyl)acrylates give rise to 3-(pyrrolo[2,1-a]isoindol-3-yl)acrylates. A further oxidative aromatization of the polycyclic intermediates provides the corresponding polycyclic pyrrolo-isoindoles and isoindolo-pyrrolo-indoles. A theoretical study on the stereoselective Diels–Alder reactions, carried out by calculating the endo/exo transition states, revealed the assistance of non-covalent interactions in governing the endo stereocontrol.

中文翻译：

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从 2-甲酰吡咯异吲哚并和吡咯并稠合的多环吲哚的不同合成中的高选择性 Diels-Alder 和 Heck 芳基化反应。

本文描述了异吲哚并和吡咯并稠合的多环吲哚的高度区域选择性、化学选择性和立体选择性发散合成，从2-甲酰吡咯开始并采用Diels-Alder和Heck芳基化反应。3-( N-苄基-2-吡咯基)丙烯酸酯和4-(吡咯-2-基)丁烯酮与马来酰亚胺进行高度内切狄尔斯-阿尔德环加成反应，得到八氢吡咯并[3,4- e ]吲哚，作为前体通过分子内 Heck 芳基化反应进行氮杂多环骨架的区域选择性合成。通过后一个反应，3-( N-苄基-2-吡咯基)丙烯酸酯产生3-(吡咯并[2,1- a ]异吲哚-3-基)丙烯酸酯。多环中间体的进一步氧化芳构化提供相应的多环吡咯并-异吲哚和异吲哚并-吡咯并-吲哚。通过计算内切/外切过渡态进行的立体选择性狄尔斯-阿尔德反应的理论研究揭示了非共价相互作用在控制内切立体控制中的帮助。