Aminomethylation Reaction of ortho-Pyridyl C–H Bonds Catalyzed by Group 3 Metal Triamido Complexes

Tris­[N,N-bis­(trimethylsilyl)­amido] complexes of group 3 metals, especially yttrium and gadolinium, served as catalysts for ortho-C–H bond addition of pyridine derivatives and N-heteroaromatics into the CN double bond of nonactivated imines to afford the corresponding aminomethylated products. Addition of catalytic amounts of secondary amines, such as dibenzylamine, dramatically improved the catalytic activity through the formation of a mixed ligated complex such as [(Me₃Si)₂N]₂Y­(NBn₂)­(THF) (4). Furthermore, kinetic studies using the isolated complex 4 provided a plausible reaction mechanism by which coordination of two pyridine derivatives afforded a penta-coordinated species as a key step.