Benzylamine, cyclometallation with

Conversion of the dinuclear cyclometallated benzylamine complex with bridging chloro ligands 476 into the mononuclear complex 477 is promoted by pyridine. The reaction proceeds via an associative pathway to form the product with the two ligating nitrogen atoms at m-positions (Equation (116). 

Most cyclometallations occur with nitrogen donor ligands benzylamine derivatives and palladium offer some examples of this ... 

Recent examples of experimental and computational studies showing the involvement of hypercoordinate intermediates are cyclometallation of benzylamine with palladium acetate (91) and cyclopalladation of aryl imino-phosphoranes (92). ... 

Scheme 6.3 Easy cyclometalation reactions with a benzylamine proceed via agostic interaction as shown in agostic intermediate 6.6 Equation (6.4) Chelation-Assisted Carbon-Halogen Bond Activation by a Rhodium(I) Complex ...

The cyclometallation of pyridazines, pyrimidines, pyrazines, and tetrazines has been studied.It was found that pyridazines formed singly and doubly cyclometallated compounds and pyrazines only metallated once. Tetrazines and pyrimidines metallate once while doubly metallated species were identified in solution. Transmetallation reactions were carried out with cyclopalladated benzylamine complexes. 

Pivalic acid displayed superior reactivity conqtared with other acidic additives (AcOH, EtC02H, and l-AdC02H). Installing electron-donating substituents onto the naphthyl moiety hampered reactivity due to decreasing N-H acidity, disfavoring cyclometalation. Benzofuran, oxazoles, and thiazoles could be effectively coupled with 1-napthylamine derivatives, and heteroary-lated pyrene systems were accessible however, benzylamine derivatives were incompatible. 

The simply prepared cyclometallated complex (24) undergoes coupling reactions with either Grignard reagents or, better, organolithium compounds, in the presence of triphenylphosphine, yielding the o-substituted benzylamines (25) (Scheme 17). The reaction also proceeds smoothly with the corresponding imino- and azo-benzenes. 

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