Enantioselective Incorporation of Amine Fragments onto Quaternary Carbons via Metallaphotoredox Catalysis

The enantioselective construction of quaternary carbon stereocenters bearing amine functionalities represents a significant challenge in organic synthesis despite their prevalence in pharmaceutically active compounds. Herein, we report a versatile metallaphotoredox platform for the asymmetric incorporation of amine fragments onto quaternary carbons via coupling of alkene‐tethered aryl bromides with readily available α‐silylamines. This transformation proceeds under mild conditions without requiring organometallic reagents or stoichiometric reductants. Mechanistically, photocatalytic generation of α‐amino alkyl radicals enables their enantioselective coupling with chiral quaternary carbon‐containing alkyl nickel species. The method delivers exceptional enantioselectivity and exhibits broad functional group tolerance, providing access to a diverse array of complex drug‐like molecules bearing amine‐functionalized quaternary stereocenters. Mechanistic investigations revealed the intermediacy of cage‐escaped, stereodefined quaternary carbon‐containing radicals, which guided the development of complementary asymmetric hydrocyclization and difluoroalkenylation protocols. Our unified platform expands the chemical space of three‐dimensional quaternary carbon scaffolds, demonstrating the potential of metallaphotoredox catalysis in addressing longstanding synthetic challenges.