Group 4 bis(pyrimidinoxide) complexes. Investigations of electronic effects in catalytic hydroamination

Substituted pyrimidinols, acidic aromatic alcohols, were used as proligands to synthesize metal complexes of Ti and Zr. These new pseudotetrahedral complexes were investigated as catalysts for the hydroamination of alkynes and alkenes. The stabilized anion of the pyrimidinoxide ligand results in enhanced electrophilicity at the metal center. These electronically modified complexes are catalytically active, but their enhanced reactivity results in reduced selectivity in comparison with the related bis(phenoxide) complexes in alkyne hydroamination. This reactivity was used to advantage in the cyclohydroamination of select aminoalkene substrates with the Zr bis(pyrimidinoxide) complex.