Cyclic Carbamates from Epoxides and Isocyanates Catalysed by Inorganic Salts

Inexpensive inorganic salts can catalyse the insertion of isocyanates to epoxides without the addition of N-heterocyclic carbene cocatalysts. Optimising catalyst, solvent and reaction temperature offers high conversions to a range of cyclic carbamates with lower reaction temperatures and greener solvents. Catalyst recyclability is also enabled by switching to a polymeric PPNCl catalyst.