Phenylene-bridged binuclear organolanthanide complexes as catalysts for intramolecular and intermolecular hydroamination

The phenylene-bridged bimetallic organolanthanide complexesp- bis{Cp''Ln[N(SiHMe2)2]2}phenylene (p-Ln2;Ln = Y, La, Cp'' = tetramethylcyclopentadienyl) and m-bis{Cp''La[N(SiHMe2)2]2}phenylene (m-La2) are investigated for possible Ln ··· Ln cooperative effects in hydroamination processes. These binuclear organolanthanide complexes efficiently catalyze the intramolecular hydroamination/cyclization of aminoalkenes, aminoalkynes, aminoallenes, and conjugated aminodienes with turnover frequencies as high as 10 h-1 at 60 °C, as well as intermolecular hydroaminations with turnover frequencies as high as 0.4 h-1 at 90 °C. Substrates include those having both compressed and extended junctures between the C-C unsaturation and the -NH2 group, as well as those with multiple -NH2 groups or places of C-C unsaturation. Reactivity trends appear to be dominated by nonbonded repulsive interactions, resulting in catalytic activities following the general trend m-Ln2 < p-Ln2. Organolanthanide amide complexes are also shown to catalyze the prototropic isomerization of alkynes.