Regioselective preferential C H activation of sterically hindered 1,3-dienes over [4+2] cycloaddition

Metal- and Solvent-Free Synthesis of Tetrahydrobenzo[c]carbazolones through NaI-Catalyzed Formal [4 + 2] Annulation

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.

Recent advances in the synthesis of carbazoles from indoles

Synthesis of carbazoles using indoles as precursors through CH activation/annulation.

Annulative π-extension of indoles and pyrroles with diiodobiaryls by Pd catalysis: rapid synthesis of nitrogen-containing polycyclic aromatic compounds

A palladium-catalyzed one-step annulative π-extension (APEX) reaction of indoles and pyrroles that allows rapid access to nitrogen-containing polycyclic aromatic compounds is described. In the presence of palladium pivalate and silver carbonate, diverse indoles or pyrroles coupled with diiodobiaryls in a double direct C-H arylation manner to be transformed into the corresponding π-extended compounds in a single step. The newly developed catalytic system enables the use of various pyrroles and indoles as templates with a series of diiodobiaryls to provide structurally complicated and largely π-extended nitrogen-containing polycyclic aromatic compounds that are otherwise difficult to synthesize.

Substrate-Controlled Regio- and Stereoselective Synthesis of ( Z)- and ( E)- N-Styrylated Carbazoles, Aza-carbazoles, and γ-Carbolines via Hydroamination of Alkynes

We report herein the substrate-controlled regio- and stereoselective hydroamination of carbazoles, aza-carbazoles, and γ-carbolines with functionalized aromatic as well as aliphatic alkynes in a KOH/DMSO system in good yields. The electronic effect of the substrates governs the stereochemistry of the product. Electron-donating alkynes provided ( Z)-stereoselective products, and electron-withdrawing alkynes provided ( E)-stereoselective products. This approach also provides an easy route for the synthesis of mono- and bis-hydroaminated product. The deuterium-labeling studies were also conducted to support the mechanistic pathway.

Ag(i)-Catalyzed cycloisomerization reactions: synthesis of substituted phenanthrenes and naphthothiophenes

Ag-Catalyzed synthesis of substituted phenanthrenes and naphthothiophenes from ortho-alkylated biaryl derivatives via 6-endo-dig intramolecular alkyne–arene coupling has been described.