Iron(III) N,N-Dialkylcarbamate-Catalyzed Formation of Cyclic Carbonates from CO2 and Epoxides under Ambient Conditions by Dynamic CO2 Trapping as Carbamato Ligands

Easily available and inexpensive FeIII carbamates were employed in the solvent-free synthesis of a series of cyclic carbonates from epoxides and CO2 at room temperature and atmospheric pressure, in the presence of a cocatalyst. Different experimental conditions (type and concentration of catalyst and cocatalyst, as well as reaction time) were investigated: Fe(O2 CNEt2 )3 and NBu4 Br acted as the best catalyst/cocatalyst combination, allowing the formation of propylene carbonate and 1,2-butylene carbonate with quantitative yield and selectivity in 24 h. According to NMR and DFT studies, the reaction proceeds with the dynamic trapping of carbon dioxide as a carbamato ligand.