4-(N,N-dimethlyamino)pyridine; dicyclohexyl-carbodiimide in dichloromethane 1.) 1 h, 0 deg C, 2.) room temperature, overnight;

triethylamine in tetrahydrofuran 4 h; Heating;

RuCl2(η-p-cymene)(PMe3) in toluene T=60°C; 6 h; other carboxylic acids and N-protected aminoacids; other ruthenium complexes; Product distribution;