Chemodivergent mechanosynthesis of cyclopentenyl and pyrrolinyl spirobarbiturates from unsaturated barbiturates and enamino esters.

A novel and interesting controllable spirocyclization of unsaturated barbiturates with enamino esters for the assembly of cyclopentenyl and pyrrolinyl spirobarbiturates has been developed under ball-milling conditions. The present protocol features high chemoselectivity and efficiency, excellent functional group tolerance and mild reaction conditions.