Carbon monoxide–isocyanide coupling promoted by acetylide addition to a diiron complex

C-N bond formation involving carbon monoxide and isocyanide ligands is promoted by addition of a series of lithium acetylides to a diiron mu-aminocarbyne complex, i.e. [Fe2{mu-CN(Me)(Xyl)}(mu-CO)(CO)(CNXyl)(Cp)2][SO3CF3] (Xyl = 2,6-C6H3Me2). The reaction proceeds in three steps, i.e. (a) acetylide addition to the CO ligand, (b) acetylide migration to the isocyanide ligand, and (c) C-N coupling. The X-ray molecular structures of 1a and 1b comprise the first example of a kappa(C,C')-N-carbonyl-aminocarbene ligand.