Catalytic amination reactions mediated by Co(II) Schiff base complexes

Co(acacen), 1, (acacen = 2,11-dihydroxy-4,9-dimethyl-5,8-diaza-2,4,8,10-dodecatetraene dianion) was found to be a highly efficient catalyst for the allylic amination of non activated alkenes, using N-(p-toluensulfonyl)iminophenyliodinane (PhIdouble bond; length as m-dashNTs) as nitrene precursor. This reactivity has been extended to the less reactive C–H bond of toluene. The effect of reaction times and of added cosolvent on yields and selectivities was investigated. Under the best conditions, allylic amines were obtained in a 40–70% isolated yield. A complex derived from the stoichiometric reaction of Co(acacen), 1, with PhIdouble bond; length as m-dashNTs has been isolated and spectroscopically characterized. Such a complex, although not able to transfer its NTs moiety to alkenes, is still active in catalyzing allylic amination of cyclohexene.