Ruthenium-Catalyzed Synthesis of Symmetrical N,N'-Dialkylureas Directly from Carbon Dioxide and Amines

Article abstract of DOI:10.1021/jo00014a024

Aliphatic and araliphatic primary amines react with carbon dioxide at 120-140 deg C in the presence of ruthenium complexes and terminal alkynes, especilly propargyl alcohols, to directly afford N,N'-disubstituted symmetrical ureas.The alkyne ruthenium intermediate acts as a dehydrating reagent.This new and mild method avoids the classical use of carbonyl precursors like phosgene or isocyanates.