title: Carbon dioxide as a carbonylating agent in the synthesis of 2-oxazolidinones, 2-oxazinones, and cyclic ureas: scope and limitations.
abstract: Carbon dioxide can be used as a convenient carbonylating agent in the synthesis of 2-oxazolidinones, 2-oxazinones, and cyclic ureas. The transient carbamate anion generated by treating a primary or secondary amine group in basic media can be activated with phosphorylating agents such as Diphenylphosphoryl azide (DPPA) and Diphenyl chlorophosphate (DPPCl) but also with other types of electrophiles such as SOCl(2), TsCl, or AcCl. The intramolecular trapping of the activated carbamate by a hydroxyl group leads to the formation of 2-oxazolidinones or 2-oxazinones in good to excellent yields. This methodology was successfully applied to the synthesis of cyclic ureas up to 7-membered rings from the corresponding diamines.
authors.affiliation: Departamento de Química Orgánica, Facultade de Química, Universidade de Vigo Campus Universitario, 36310 Vigo, Spain.
authors.forename: Jairo
authors.initials: J
authors.lastname: Paz
authors.forename: Carlos
authors.initials: C
authors.lastname: Pérez-Balado
authors.forename: Beatriz
authors.initials: B
authors.lastname: Iglesias
authors.forename: Luis
authors.initials: L
authors.lastname: Muñoz