Benzyne-benzyne-RNC or CO triple sequential insertion into the Pd-C bond: synthesis of ten-membered N-heterocycles through stable ten- and eleven-membered palladacycles.

Insertion of two molecules of benzyne into the Pd-C bond of an ortho-palladated derivative of homoveratrylamine allows the synthesis and XRD characterization of a ten-membered palladacycle, which further reacts with CO or RCN to afford, upon depalladation, tribenzazecine derivatives. The iminoacyl eleven-membered palladacycle intermediate can also be isolated.