Enantioselective Organocatalytic Addition of Azlactones to Maleimides: A Highly Stereocontrolled Entry to 2,2‐Disubstituted‐2H‐oxazol‐5‐ones

The first highly diastereo- and enantioselective organocatalytic synthesis of 2,2-disubstituted-2H-oxazol-5-ones is described. The addition of oxazolones to maleimides is promoted by bifunctional thiourea catalysts, which afford the corresponding 2,2-disubstituted-2H-oxazol-5-ones with total regio- and stereocontrol.