Insertion reactions of titanium alkoxides with isocyanates and carbodiimides

Abstract

Titanium alkoxides react readily and reversibly with isocyanates by insertion into the Ti–O bond to form mono-, di-, tri-, or tetra-N-titano-urethanes. With titanium aryloxides the reaction is much slower and irreversible. Carbodiimides react in a similar manner to give only the di-substituted-N-titanoisoureas. The repetitive insertion of isocyanates to give linear polymer (nylon-1) or cyclic trimers is also observed. The above examples constitute the first known examples of tetra-insertion into a metal alkoxide.