Cobalt‐Catalyzed Enantioselective Hydroamination of Arylalkenes with Secondary Amines

Catalytic asymmetric hydroamination of alkenes with Lewis basic amines is of great interest but remains a challenge in synthetic chemistry. Here, we developed a Co‐catalyzed asymmetric hydroamination of arylalkenes directly using commercially accessible secondary amines. This process enables the efficient access to valuable α‐chiral tertiary amines in good to excellent yields and enantioselectivities. Mechanistic studies suggest that the reaction includes a CoH‐mediated hydrogen atom transfer (MHAT) with arylalkenes, followed by a pivotal catalyst controlled SN2‐like pathway between in situ generated electrophilic cationic alkylcobalt(IV) species and free amines. This radical‐polar crossover strategy not only provides a straightforward and alternative approach for the synthesis of enantioenriched α‐tertiary amines, but also underpins the substantial opportunities in developing asymmetric radical functionalization of alkenes with various free nucleophiles in oxidative MHAT catalysis. An excellent enantioselective hydroamination of arylalkenes with Lewis basic secondary amines was developed, via an elegant cobalt‐hydride mediated oxidative hydrogen atom transfer (MHAT) process, leading to the synthesis of a series of valuable α‐chiral tertiary amines in good to excellent yields and enantioselectivities.