Formylation of Amines with CO2 Using a Polymeric Frustrated Lewis Pair
Polymer Meets Frustrated Lewis Pair: Second-Generation CO2-Responsive Nanosystem for Sustainable CO2 Conversion.
Angew. Chem. Int. Ed. 2018;
17 September 2018 (online)
A polymeric carbon dioxide bridged frustrated Lewis pair (A) was prepared by treatment of an electron-deficient triarylborane immobilized on polystyrene with a sterically demanding triarylphosphine immobilized on polystyrene in the presence of CO2 (eq. 1). The polymeric frustrated Lewis pair A catalyzed the formylation of amines with carbon dioxide in the presence of phenylsilane at room temperature to give the corresponding formamides in up to 99% yield (eq. 2). The turnover number for the formylation reached as high as 14800.
The polymeric frustrated Lewis pair A was characterized by 11B, 19F, and 31P NMR, DLS, TEM, FT-IR, UV-Vis, and conductivity measurements. In the formylation of diethylamine, morpholine, aniline, benzophenone imine, or imidazole, the catalyst was reused seven times with slight loss of the catalytic activity.