High-boiling polar aprotic solvent which has been recommended as a replacement for the carcinogenic hexamethylphosphoric triamide, HMPA. It is stable to alkali metals and strong bases: J. Organomet. Chem., 92, C46 (1975); 117, 149 (1976). For example, it has been used as a solvent for the displacement of non-activated aryl halides by thiolates: Tetrahedron Lett., 23, 4131 (1982); J. Org. Chem., 44, 2642 (1979); 45, 4376 (1980); and as a superior solvent in the Ullmann aryl ether synthesis: Chem. Lett., 899 (1988).
