A Highly Stable CM@Co ₃ O ₄ Photocatalyst for the Sustainable Synthesis of α‐Amino Acetals via Base‐Assisted C(sp ³ )‐H Functionalization

Abstract The synthesis of α‐amino acetals via radical addition of 1,3‐dioxolane to imines has attracted considerable attention, though conventional methods face stability and recyclability challenges due to their reliance on stoichiometric organometallic reagents or homogeneous catalysts. To address this, we developed a heterojunction photocatalyst comprising Co 3 O 4 nanoparticles supported on porous carbon nitride (CM@Co 3 O 4 ). This design leverages the excellent substrate properties of carbon nitride and band‐aligned Co 3 O 4 to enhance charge separation. The resulting heterogeneous system exhibits remarkable stability and superior photocatalytic efficiency. Combined with base additives (e.g., Cs 2 CO 3 ), this method enables efficient visible‐light‐driven synthesis of α‐amino acetals in air and at room temperature. This method not only demonstrates excellent catalytic activity and cyclic stability (reusable up to 10 times), but also shows applicability to various N ‐benzylideneaniline substrates (with up to 93% yield). Mechanistic studies‐including radical trapping, electron spin resonance (ESR), 1 H nuclear magnetic resonance (NMR) titration, and density functional theory (DFT) calculations‐indicate that the base and photocatalyst synergistically promote hydrogen abstraction mediated by photogenerated holes, generating key radical intermediates that drive subsequent reactions. This study provides a new, efficient and practical pathway for the green synthesis of the α‐amino acetals.