Direct Amide Synthesis from Alcohols and Amines by PhosphineFree Ruthenium Catalyst Systems

Amides are synthesized directly from alcohols and amines in high yields using an in situgenerated catalyst from easily available ruthenium complexes such as the pcymeneruthenium dichloride dimer, RupcymemeCl22, or the benzeneruthenium dichloride dimer, RubenzeneCl22, an Nheterocyclic carbene NHC ligand, and a nitrogen containing Ltype ligand such as acetonitrile. The phosphinefree catalyst systems showed improved or comparable activity compared to previous phosphinebased catalytic systems. The in situgenerated catalyst from RubenzeneCl22, an NHC ligand, and acetonitrile showed excellent activity toward reactions with cyclic secondary amines such as piperidine and morpholine.