Selective radical amination of aldehydic C(sp~2)-H bonds with fluoroaryl azides via Co(II)-based metalloradical catalysis: synthesis of N-fluoroaryl amides from aldehydes under neutral and nonoxidative conditions

摘要

The Co(ii) complex of the D_(2h)-symmetric amidoporphyrin 3,5-Di~tBu-lbuPhyrin, [Co(P1)], has proven to be an effective metalloradical catalyst for intermolecular amination of C(sp~2)-H bonds of aldehydes with fluoroaryl azides. The tCo(P1)] -catalyzed process can employ aldehydes as the limiting reagents and operate under neutral and nonoxidative conditions, generating nitrogen gas as the only byproduct. The metalloradical aldehydic C-H amination is suitable for different combinations of aldehydes and fluoroaryl azides, producing the corresponding N-fluoroaryl amides in good to excellent yields. A series of mechanistic studies support a stepwise radical mechanism for the Co(II)-catalyzed intermolecular C-H amination.