Reactivity of naphthylimines toward Fe-2(CO)(9): Observation of three different hydrogen migration pathways

The reaction of Fe-2(CO)(9) with imine ligands derived from alpha- or beta- naphthylcarbaldehydes leads to the formation of a series of iron carbonyl c omplexes. Most of them are produced by a C-H activation reaction in ortho p osition with respect to the exocyclic imine function. The reaction then pro ceeds via subsequent intramolecular hydrogen shift reactions and leads to s everal dinuclear compounds. Three different types of these hydrogen-transfe r reactions were observed: a 1,3 hydrogen shift toward the former imine car bon atom, a 1,4 hydrogen shift toward the former imine nitrogen atom, or a 1,3 shift reaction toward one of the aromatic carbon atoms of the naphthale ne system, which thus leaves the exocyclic imine function unreacted. In the reaction of beta-naphthyl derivatives the formation of trinuclear complexe s is observed by the eta(4)-coordination of a third Fe(CO)3 group to the se cond ring of the naphthalene. Besides this, the first example of a structur ally characterized (eta(4)-1-azadiene)Fe(CO)(3) complex with the C-C double bond formally being part of a cyclic aromatic system is obtained as a bypr oduct.