Christian Laporte

Investigations in the catalytic species of the distannoxane-catalyzed transcarbamoylation

1,3-Dihalodistannoxanes show a high activity as catalysts in transcarbamoylation, explained by the weak coordinative properties of the halogens, and act as Lewis acid and not alkoxide carriers in the catalytic cycle.

Efficient bismuth catalysts for transcarbamoylation

Among some bismuth catalysts, bismuth trifluoromethanesulfonate showed excellent catalytical properties in the transcarbamoylation reaction between a N-alkyl O-alkyl carbamate and a primary alcohol. It was found more active than classical organotin catalysts. Moreover it was also more selective as no alkyl isocyanate was detected during the transcarbamoylation.

Dichlorodistannoxane transesterification catalysts, pure Lewis acids.

Dialkoxy- or diacyloxy-distannoxanes were transformed into unsymmetrical acyloxyalkoxydistannoxanes during a transesterification reaction where they were used as catalysts, while more active dichlorodistannoxanes were recovered unchanged.