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.
CoCl2‐catalyzed formal [5+2] oxidative annulation of o‐arylanilines with alkynes was developed, giving access to various important imine‐containing dibenzo‐[b,d]azepine scaffolds through sequential C−C/C−N bond formation. The reaction employs catalytic amount of manganese and oxygen as cooxidants, and features a broad substrate scope. Preliminary mechanistic studies suggested that C−Hactivation is involved