Insight into O2-Promoted Base-Catalyzed N-Alkylation of Amines with Alcohols

A highly efficient and practical transition-metal-free CsOH/O-2 catalyst system was developed for the N-alkylation of amines with alcohols under argon. This strategy was compatible with many alcohols and exhibits excellent functional group tolerance. More significantly, the selective formation of secondary amines was achieved in excellent yields. The detailed mechanistic study gave a clear understanding of the role of base and oxygen in the catalytic cycle.