Hydride addition at μ-vinyliminium ligand obtained from disubstituted alkynes

NaBH4 gives addition at the bridging vinyliminium ligand in the diiron complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ (R″)CαN(Me)(R)}(μ-CO)(CO)(Cp)2] [SO3CF3] (R′ and R″ = alkyl or aryl substituents, R = Me, CH2Ph or Xyl). Depending on the nature of these substituents and on the geometry of the parent complexes cis or trans, H− addition occurs selectively at the iminium carbon (Cα) or at the adjacent Cβ position, affording complexes of the type 5d or 6a, respectively.