Synthesis of Carbazoles by Copper-Catalyzed Intramolecular C–H/N–H Coupling
摘要:
A Cu-catalyzed intramolecular C-H amination for the synthesis of carbazoles has been developed. The key to success is the installation of the picolinamide-based directing group, which is spontaneously removed after the coupling event. The Cu catalysis proceeded smoothly under Pd- and I(III)-free conditions, and its mild oxidation aptitude enables the rapid and concise construction of heteroatom-incorporated carbazole core pi-systems.
Synthesis of Carbazoles by Copper-Catalyzed Intramolecular C–H/N–H Coupling
摘要:
A Cu-catalyzed intramolecular C-H amination for the synthesis of carbazoles has been developed. The key to success is the installation of the picolinamide-based directing group, which is spontaneously removed after the coupling event. The Cu catalysis proceeded smoothly under Pd- and I(III)-free conditions, and its mild oxidation aptitude enables the rapid and concise construction of heteroatom-incorporated carbazole core pi-systems.
The iridium-catalyzed dehydrogenative cyclization of 2-aminobiphenyls proceeds smoothly in the presence of a copper cocatalyst under air as a terminal oxidant through intramolecular direct C-H amination to produce N-H carbazoles. A similar iridium/copper system can also catalyze the unprecedented dimerization reaction of 2-aminobiphenyl involving 2-fold C-H/N-H couplings.