Reaction of dibutyltin oxide with methanol under CO2 pressure relevant to catalytic dimethyl carbonate synthesis

Dibutyltin oxide (Bu2SnO)n (3) reacts with methanol to give the tetrabutyl(dimethoxy)stannoxane dimer (4). The presence of 2,2-dimethoxypropane under a CO2 pressure accelerates the reaction resulting in nearly quantitative yield. Complex 4 exhibits catalytic activity as high as that of {Bu2Sn(OMe)2}2 (1) in the dimethyl carbonate (DMC) synthesis from CO2 and methanol. These results indicate that the conversion of 3 to 4 occurs under catalytic DMC production conditions.