A novel strategy for the preparation of functional carbazoles through NaI-catalyzed formal [4 + 2] annulation of 2-(indol-3-yl)­cyclohexanones and alkynes/alkenes has been developed. The present approach started from easily available raw materials and provided a variety of tetrahydrobenzo­[c]­carbazolones in satisfactory yields under metal- and solvent-free conditions. Furthermore, the products could be further transformed into structurally valuable carbazole-based conjugated derivatives.

A metal-and solvent-free strategy for the preparation of maleimide-fused carbazoles has been developed. This protocol started from 2-(indol-3-yl)cyclohexanones and maleimides, providing various maleimide-fused carbazoles in 45-90% yields. The present approach was catalyzed by trimethylsulfoxonium iodide and involved a cascade of oxidation, [4 + 2] annulation, and dehydrogenative aromatization. Moreover, these maleimide-fused carbazole products could be further transformed into other polycyclic aromatic hydrocarbons.

A four-component synthesis of tetrasubstituted pyrroles was developed under metal-free conditions. The pyrrole ring was formed in one pot through [2 + 1 + 1 + 1] condensation using ammonium salt as the nitrogen source. In this strategy, 1,4-naphthoquinones and maleimides were used as the versatile C2 fragments to provide substituted benzo[f]isoindole-4,9-diones and pyrrolo[3,4-c]pyrrole-1,3-diones, respectively. This work is highlighted by using ammonium salt as the nitrogen source, readily available starting materials and multibond formation (two C–C and two C–N bonds) in a single operation.

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Comprehensive Summary A three‐component synthesis of benzo[α]phenanthridines from aromatic aldehydes, cyclohexanones, and aromatic amines has been developed, which is mediated by KI/DMSO/camphorsulfonic acid to afford a variety of functionalized benzo[α]phenanthridines in satisfactory yields. The present strategy provides a biaryl motif ortho to the nitrogen atom which has the potential to be used as ligand by further modification. With the advantages of readily available starting materials, transition‐metal‐free conditions, gram‐scale synthesis, and broad substrate scope, this three‐component protocol provides an efficient approach for the preparation of diverse benzo[α]phenanthridines.