Reaction of carbon dioxide with oxetane catalyzed by organotin halide complexes: Control of reaction by ligands

Article abstract of DOI:10.1021/om00144a024

Complexes of organotin iodides with phosphines or phosphine oxides catalyze the addition of carbon dioxide to oxetane, giving trimethylene carbonate and polycarbonate. The choice of a ligand is crucial. All the complexes with Bu₃P gave polycarbonate, but the combination of Bu₃SnI with Bu₃P=O yielded trimethylene carbonate exclusively in good yields. The complex Bu₂SnI₂·Bu₃P=O had no catalytic activity in the formation of either polycarbonate or trimethylene carbonate. The coordination mode of ligands and the stability of the complexes seem to be important. The function of ligands is suggested not only to involve activation of the tin-halogen bond but also to decrease the acidity of tin compounds, thus suppressing polymerizations.