[4+2]‐Cycloaddition of para ‐Quinone Methides with Hexahydro‐1,3,5‐Triazines: Access to 1,3‐Benzoxazine Derivatives

A [4+2]‐cycloaddition of para ‐quinone methides with hexahydro‐1,3,5‐triazines is reported. The reaction occurs under very mild conditions (catalyst‐, ligand‐, and base‐free), exhibits a broad substrate scope and excellent functional group tolerance, and affords a series of biologically important 1,3‐benzoxazine derivatives in good to excellent yields. Moreover, the successful late‐stage functionalization of pharmaceutically relevant compounds further renders the approach valuable. magnified image