Bidentate pyrrolyl lithium complexes: Synthesis, crystal structure and catalytic activity for the cyclotrimerization of isocyanates

A convenient and practical method for the cyclotrimerization of isocyanates is described. The reaction is catalyzed in the presence of catalytic amounts (0.1 mol%) of lithium compounds containing substituted pyrrolyl ligands leads to the corresponding isocyanurates in high yields (up to 98%).