Lignin-derived Zn single atom/N-codoped porous carbon for α-alkylation of aromatic ketones with alcohols via borrowing hydrogen strategy

A green and scalable strategy has been developed for the synthesis of lignin-derived Zn single atom/N-codoped porous carbon (LCN@Zn-SAC) containing similar ZnN_x sites with carbonic anhydrases. This catalyst exhibits superior activity on the α-alkylation of ketones with alcohols via borrowing hydrogen strategy (TON up to 15 h⁻¹) than most of previously reported works. The dehydrogenation of benzyl alcohol is the rate-determining step based on kinetic experiment results. According to experimental and theoretical calculation results, Zn electron density is inversely proportional to reaction energy barriers, because Zn sites with less positive charge (ZnN₄ and ZnN₃C) in Zn-SACs display better borrowing hydrogen ability than other Zn sites. Furthermore, this catalyst can be recycled by simple centrifugation, which can be reused at least 8 runs with no obvious lose in activity. To the best of our knowledge, this is the first example of non-noble metal-SAC-catalyzed α-alkylation via borrowing hydrogen strategy.