A novel migratory insertion reaction is disclosed utilizing organoaluminum compounds. An intramolecular transfer of a carbon group from the aluminum complex E-1-halo-1-alkenyl)trialkylalanate occurs to produce an E-alkenyl(alkoxy)dialkylalanate or an E-dialkylalkenylalane or an (E,E)-3-alkyl-2-dialkylalumino-1,3-diene depending on process conditions. Novel organic aluminates are also disclosed.