Selective Iridium-Catalyzed Alkylation of (Hetero) Aromatic Amines and Diamines with Alcohols under Mild Reaction Conditions

A P,N-ligand-coordinated iridium complex has been employed as an efficient catalyst for the selective monoalkylation of (hetero)aromatic amines with alcohols. A significant improvement of this alkylation method has been achieved, such that it can be performed at a temperature of 70 degrees C and with catalyst loadings as low as 0.1 mol% Ir, while still affording excellent yields of secondary amines. Furthermore, the high selectivity of this catalyst for the monoalkylation of aromatic amino functions has been successfully exploited for the alkylation of diamines in both symmetric and non-symmetric fashions, providing a novel and very efficient synthetic tool for the preparation of N,N'-dialkylated aromatic diamines.