Iron salts catalyze the allylic amination of alkenes by arylhydroxylamines in moderate to good yields and with high regioselectivity resulting from double-bond transposition. The iron-catalyzed reaction of phenylhydroxylamine with representative alkenes in the presence of 2,3-dimethylbutadiene, an effective PhNO trap, produces allyl amines exclusively, excluding the intermediacy of free PhNO in the amination reaction. The reaction of FeCl2,3 with PhNO or PhNHOH produces a novel azo dioxide iron complex, {Fe[Ph(O)NN(O)Ph](3)}[FeCl4](2) (1a), whose structure has been established by X-ray diffraction. The structure of 1a features essentially tetrahedral Fe(III)Cl-4-anions and a novel six-coordinate dication having iron(II) bound through the oxygens of three azobenzene N,N-dioxide ligands. Evidence that 1a is the active aminating agent in the catalytic reactions includes (1) its isolation from the catalytic reaction; (2) its facile reaction with alkenes to produce allyl amine in high yield and regioselectivity; (3) its amination of alkenes without the intervention of free PhNO; and (4) its efficient catalysis of amination by PhNHOH. The reaction of 2-methyl-2-pentene (2-MP) with 1a (dioxane, 70 degrees C) was examined kinetically; the appearance of allylamine was found to be first order in 1a and first order in alkene. Rate constants determined for the reactions of 1a with a set of para-substituted alpha-methylstyrenes lead to a Hammett rho value of -3.0. A small kinetic D-isotope effect, 1.4 +/- 0.2, is found for the intermolecular amination of alpha-(trideuteriomethyl)styrene by 1a. Low-temperature reactions of 1a with 2-MP, beta-methylstyrene, and styrene produce isolable alkene adducts 3a-c. Thermolysis of 3a in dioxane gives the corresponding allyl amine while treatment of 3a-c with nitrosoarenes regenerates the respective alkenes. IR, NMR, and UV-vis spectroscopic data also support the formulation of 3a-c as alkene complexes. Evidence that azo dioxide complex 1 transfers a PhNO (rather than PhN) unit to alkene, producing an intermediate allylhydroxylamine which is subsequently reduced to the ultimate allyl amine, is provided from model reaction studies and GC/MS monitoring. Various mechanistic pathways are presented and analyzed. The mechanism most consistent with all of the accumulated evidence involves alkene coordination to 1 via dechelation of an azo dioxide ligand, intramolecular RNO transfer to coordinated alkene to produce the allylhydroxylamine, reductive deoxygenation of the allylhydroxylamine to allylamine, and regeneration of azo dioxide complex 1 by oxidation of another PhNHOH molecule by iron(III).