The acetate complex Ru(OAc)2 (DiPPF) (2) obtained from Ru(OAc)2 (PPh3 )2 (1) and 1,1'-bis(diisopropylphosphino)ferrocene (DiPPF) reacts cleanly with formaldehyde affording Ru(OAc)2 (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, PhCH2 ) 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 NEt3 at RT through an equilibrium reaction.
Keywords: N-alkylation; alcohols; amines; borrowing hydrogen; ruthenium.
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