Ketenimine for Nitrile Rearrangements in N-Arylmethyl Ketenimines: [1,n] Migrations of Bulky Arylmethyl Groups

C,C-Diphenyl ketenimines bearing a benzoannulated benzyl group at the nitrogen atom undergo facile 1,3-, 1,5- and 1,7-migrations of the bulky arylmethyl group to the sp2 terminal carbon atom of the ketenimine function and to the ortho and the para positions of one of the C-phenyl substituents.