Synthesis of C4-Aminated Carbazoles and Their Derivatives via Pd/NBE Chemistry.

Carbazole, as one of the most important organic frameworks, has been used in optoelectronic materials and biochemistry. However, the synthesis of C4-substituted carbazole has always been an unsolved problem. This report describes the one-step synthesis of C4-aminated carbazoles and their derivatives through the series reaction of C-H amination and arylation. The substrate scope is wide. C4-Amino carbazoles substituted by C2, C6, C7, and C8 methyl groups, especially carbazole derivatives of fused rings, pyridine, and dibenzofuran, can be synthesized.

Template Synthesis to Solve the Unreachable Ortho C-H Functionalization Reaction of Aryl Iodide.

This report describes the use of a simple Pd/NBE catalytic system to achieve ortho C-H oxylation and phosphonylation and other functionalizations of aryl iodide through templated conversion reactions. Dimethylamine is introduced in the ortho-site of aryl iodide through C-H amination, and aryl dimethylamine is quickly converted to methyl quaternary ammonium salt precipitation. Methyl quaternary ammonium salt avoids Hofmann elimination in subsequent functionalization. This method solves various ortho functionalization reactions of aryl iodide that have not been achieved for a long time in the field of Pd/NBE chemistry indirectly.

Synthesis of C8-Aminated Pyrrolo-Phenanthridines or -Indoles via Series C(sp2 or sp3)-H Activation and Fluorescence Study.

This report developed a method for the synthesis of C8-aminated pyrrolo-phenanthridines or -indoles by series ortho C(sp2)-H amination/ipso C(sp2)-H or C(sp3)-H arylation. N-benzoyloxyamines, as electrophilic amination reagents, did not undergo an electrophilic substitution reaction with the pyrrole side, but they did undergo a site-selective C-H amination reaction with the benzene side via Pd/NBE catalysis. The C8-aminated pyrrolo-phenanthridines have strong fluorescence in solution and solid state. X-ray single crystal diffraction shows that the steric hindrance of amino and ortho benzene ring may inhibit aggregation-caused quenching (ACQ).

Directed Copper-Catalyzed Tandem Radical Cyclization Reaction of Alkyl Bromides and Unactivated Olefins.

The free radical cyclization reaction is a promising strategy for ring framework formation. Herein, we report a copper-catalyzed tandem radical cyclization strategy for preparing substituted lactam derivatives. This reaction proceeds through a radical coupling approach, which not only allows a wide range of alkenes but also is quite compatible with the primary, secondary, and tertiary radicals. In addition, density functional theory calculations were performed to gain insights into the reaction mechanism.

Palladium-Catalyzed Synthesis of Tricyclic Indoles via a N-S Bond Cleavage Strategy.

In palladium/norbornene (Pd/NBE) chemistry, the "ortho effect" has been proven to be a key factor in the process of ß-carbon elimination to extrude NBE. Herein, we found that the o-iodoaniline protected by a p-methoxybenzenesulfonyl group can recover the "ortho effect" and then undergo N-S bond cleavage with vinyl palladium, thus achieving a highly selective C-N coupling reaction in the Catallani-Lautens reaction system. On the basis of this discovery, a one-step synthesis of highly functionalized tricyclic indole derivatives was realized.