Co(II)-porphyrin complexes catalyze the reaction of aromatic azides (ArN(3)) with hydrocarbons that contain a benzylic group (ArR(1)R(2)CH) to give the corresponding amines (ArR(1)R(2)C-NHAr). When at least one of the R substituents is hydrogen, the catalytic reaction proceeds further to give the imine ArRC=NAr in good yields. The reaction mechanism has been investigated. The reaction proceeds through a reversible coordination of the arylazide to the Co(II)-porphyrin complex. This unstable adduct can either react with the hydrocarbon in the rate-determining step or decompose by a unimolecular mechanism to afford a putative "nitrene" complex, which reacts with more azide, but not with the hydrocarbon, to afford the byproduct diaryldiazene. The kinetics of the catalytic reaction have been investigated for a range of azides and substituted toluenes. Arylazides with electron-withdrawing substituents react at a faster rate and a good correlation is found between the log(k) and the Taft parameters. On the other hand, an excellent correlation between the logarithm of the rate for substituted toluenes relative to that of toluene and a radical parameter (sigma*JJ) alone was found, with no significant contribution by polar parameters. An explanation has been proposed for this anomalous effect and for the very high isotopic effect (k(H)/k(D)=14) found.

Keywords: Cobalt / Cyclopropanation / Olefins / PorphyrinoidsCobalt(II) porphyrin complexes catalyze reactions between ethyl diazoacetate (EDA) and styrenes to give the corresponding cyclopropanes with trans selectivity. The reactions of other diazoalkanes and other olefins have also been carried out, and the mechanism of the reaction has been investigated. Kinetic data and stoichiometric reactions support the formation of a diazoalkane cobalt-porphyrin complex that reacts with the olefins to generate the cyclopropane. Diethyl

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A reaction is reported, resulting in the allylic amination of an unactivated olefin, cyclohexene, by a nitroarene, catalyzed by Ru3(CO)12/Ar-BIAN (Ar-BIAN = bis(arylimino)acenaphthene), under CO pressure. The reaction involves an intermolecular catalytic C−H functionalization by a transition metal complex. Best results (selectivity up to 81.9%, with a substrate/Ru3(CO)12 ratio = 50) are obtained by using nitroarenes bearing electron-withdrawing substituents and Ph-BIAN as a ligand. Other olefins can also be employed in place of cyclohexene. The reaction mechanism has been investigated. The reaction is first order in nitroarene and olefin, which is used as solvent in most cases, but the rate equation also contains an olefin-independent term. A rate acceleration by small amounts of toluene in the solvent mixture is due to a faster formation of Ru(CO)3(Ar-BIAN) from Ru3(CO)12 and Ar-BIAN in its presence. This last complex is in equilibrium with the active species Ru(Ar-BIAN)(CO)2(cyclohexene), and its direct reaction with the nitroarene accounts for the olefin-independent term in the rate law. The reaction of Ru(CO)3(Ar-BIAN) with nitroarenes gives Ru(CO)2(Ar-BIAN)(η2-ArNO), which has been isolated in one case, but this complex is not an intermediate in the synthesis of allylamines. Coupling between a coordinated nitrosoarene and a coordinated olefin appears to be responsible for the C−N bond formation.

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