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 (PhI=NTs) 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 PhI=NTs 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.