Phenylene-Bridged Binuclear Organolanthanide Complexes as Catalysts for Intramolecular and Intermolecular Hydroamination

The phenylene-bridged bimetallic organolanthanide complexes p -bis{Cp′′Ln[N(SiHMe 2 ) 2 ] 2 }phenylene ( p -Ln 2; Ln = Y, La, Cp′′ = tetramethylcyclopentadienyl) and m -bis{Cp′′La[N(SiHMe 2 ) 2 ] 2 }phenylene ( m -La 2 ) 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 −NH 2 group, as well as those with multiple −NH 2 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 -Ln 2 < p -Ln 2 . Organolanthanide amide complexes are also shown to catalyze the prototropic isomerization of alkynes.