Spiroindolines and spiroindoles are an important class of spirocyclic compounds present in a wide range of pharmaceuticals and biologically important natural alkaloids. Various spiroindolines and spiroindoles possess versatile reactivity which enables them to act as precursors for other privileged heterocycles. In view of the importance of this scaffold, many researchers focused their efforts to develop facile and mild synthetic methods for spirocyclization of indoles. However, the synthesis of spiroindolines and spiroindoles is known to be difficult due to rapid 1,2-migration to restore aromaticity. This review aims to briefly discuss the latest developments to access highly functionalized spiroindolines and spiroindoles to stimulate further research in the field to find new and efficient methodologies for accessing new spiroindolines and spiroindoles.

中文翻译：

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吲哚衍生物螺环化的最新进展

螺吲哚啉和螺吲哚是在许多药物和生物学上重要的天然生物碱中存在的一类重要的螺环化合物。各种螺二氢吲哚和螺螺吲哚具有通用的反应性，使它们能够充当其他特权杂环的前体。考虑到该支架的重要性，许多研究人员集中精力开发用于吲哚螺环化的简便且温和的合成方法。然而，由于快速的1，2-迁移以恢复芳香性，已知螺二氢吲哚和螺吲哚的合成是困难的。