Metal N,N-dialkylcarbamates as easily available catalytic precursors for the carbon dioxide/propylene oxide coupling under ambient conditions

Recent Advances in the Chemistry of Metal Carbamates

“…Recently, the study of the reactivity of homoleptic N,N-dialkylcarbamates with silica has been extended to Cu(II), Nb(III), Nb(V), Ta(V), Tb(III) and Eu(III) derivatives [131,153,362,363]. Silica grafting has been also realized with non-homoleptic complexes of group 4 and 5 metals, wherein the carbamato ligands are the most reactive ones [166,234,290]. Even magnetite nanoparticles [364] and silica/zirconia [362] have been decorated with metal carbamates.…”

“…Silica-grafted metal carbamato species have been investigated for their catalytic properties compared to the homogeneous congeners [290]. In addition, the grafted carbamato complex may undergo subsequent chemical modifications.…”

“…Furthermore, metal carbamates might be susceptible to transamination, exchanging the internal R 2 N group with that coming from an external amine. This feature was exploited for the preparation of [Al(O 2 CNEt 2 ) 3 ] [ 290 ], [Nd(O 2 CNEt 2 ) 3 ] [ 145 ], [Eu(O 2 CNBn 2 ) 3 ] and [Sm(O 2 CNBn 2 ) 3 ] [ 151 ], taking advantage of the volatility of the outgoing amine and/or the lower solubility of the metal carbamato product.…”

Recent Advances in the Chemical Fixation of Carbon Dioxide: A Green Route to Carbonylated Heterocycle Synthesis

“…Propylene carbonate was also obtained from propylene oxide at atmospheric CO 2 pressure and at ambient temperature, by using various metal carbamates, such as Ti(O 2 CNEt 2 ) 4 , Al(O 2 CNR 2 ) 3 (R=Et, i-Pr), Cu(O 2 CNEt 2 ) 2 and Sn(O 2 CNEt 2 ) 4 , in combination with NBu 4 X (X=Br or Cl) as a cocatalyst [126]. With different catalyst and cocatalyst amounts, conversion up to 71% and selectivity up to >99% were reached.…”

Carboxylation of terminal alkynes promoted by silver carbamate at ambient pressure

“…Analogously, carbamates of tin, aluminum and copper are active in the epoxide-CO2 coupling process under mild conditions. 23 Herein, we explore for the first time the catalytic potential of copper and silver carbamates, showing their performance in the carboxylation reactions of terminal alkynes.…”