Mild N-Alkylation of Amines with Alcohols Catalyzed by the Acetate Ru(OAc) (CO)(DiPPF) Complex.

The acetate complex Ru(OAc) (DiPPF) (2) obtained from Ru(OAc) (PPh )  (1) and 1,1'-bis(diisopropylphosphino)ferrocene (DiPPF) reacts cleanly with formaldehyde affording Ru(OAc) (CO)(DiPPF) (3) in high yield. The monocarbonyl complex 3 (0.4-2 mol %) efficiently catalyzes the N-alkylation of primary and secondary alkyl and aromatic amines using primary alcohols ROH (R=Et, nPr, nBu, PhCH ) under mild reaction conditions (30-100 °C) with an alcohol/amine molar ratio of 10-100. Formation of the monohydride RuH(OAc)(CO)(DiPPF) (4) has been observed by reaction of 3 with iPrOH in the presence of NEt at RT through an equilibrium reaction.