Recent Advances and Perspectives in the Synthesis and Applications of Tetrahydrocarbazol‐4‐ones†

Tetrahydrocarbazol‐4‐one represents a prevalent framework of numerous natural products and pharmaceuticals. This review summaries the recent synthetic progresses of this core structure, including Fischer indolization, oxidative and reductive coupling, α‐arylative cyclization by means of transition‐ metal catalysis or under metal‐free conditions, and other methods. The recently emerged enantioselective catalytic methods of tetrahydrocarbazol‐4‐ ones are also described. The mechanistic insights and applications of these strategies as a key step in the total (formal) synthesis of complex alkaloids are highlighted as well.