Convergent and Diversity-Oriented Synthesis of Indoline-Based Tricyclic Systems via an Indole-Involved Povarov Reaction

An indole-involved Povarov reaction between indole-derived aldehydes and arylamines is reported, enabling convergent and diversity-oriented access to newly developed indoline-based [5-6-6] and [5-6-5] tricyclic frameworks in one step with good to excellent yields. This protocol exhibits a broad substrate scope and excellent functional-group compatibility while maintaining complete diastereoselectivity. Photophysical evaluations of representative [5-6-6] molecules reveal promising fluorescence properties, underscoring their potential as fluorescent dyes and motivating further applications.