Mechanism of Insertion of Carbodiimides into the Zr−C Bonds of Zirconaaziridines. Formation of α-Amino Amidines

Treatment of zirconaaziridines Cp 2 Zr-η 2 -[N(R 1 )CH(R 2 )](THF) with carbodiimides results in the insertion of the carbodiimide into the Zr−C bonds. The insertion of bis(trimethylsilyl)carbodiimide is reversible, which becomes significant at high THF concentrations. Kinetic data indicate that the THF ligand must dissociate prior to carbodiimide insertion. Protic cleavage of the organic fragment from zirconium results in formation of α-amino amidines.