Organocatalytic functionalization of heteroaromatic N-oxides was investigated using in situ generated onium amide bases, and C-nucleophiles were efficiently introduced by the sequential addition–elimination reaction under metal-free conditions, affording 2-substituted nitrogen heteroaromatics generally in good to high yields.
Synthesis of Benzoacridines and Benzophenanthridines by Regioselective Pd-Catalyzed Cross-Coupling Reactions Followed by Acid-Mediated Cycloisomerizations
Various benzoacridines and benzophenanthridines have been synthesized by Brønsted acid mediated cycloisomerisation as the key step. The optical and electrochemical properties have been studied by UV/Vis and emission spectroscopy as well as CV measurements. Obtained results have been verified by DFT calculations.
An efficient potassium hydroxide‐catalyzed alkynylation of heteroaromatic N‐oxides under transition‐metal‐free conditions with the assistance of visible‐light has been developed. Various C2‐alkynylheterocycles were obtained in up to 92% yield with good functional group tolerance. This new method is operational simple, highly efficient, atom economic, and environmental friendly.