A Cross-Metathesis/Aza-Michael Reaction Strategy for the Synthesis of Cyclic and Bicyclic Ureas

The synthesis of cyclic and bicyclic ureas via a ruthenium-catalyzed cross-metathesis / aza-Michael reaction strategy between protected alkenyl ureas and Michael acceptors is described. The substrates for these reactions are generated in 1–3 steps from commercially available materials, and products are formed in moderate yield with up to >20:1 diastereoselectivity.