Acrylate-Assisted Arene-Chromium Bond Cleavage: Generation of a [Cr(CO)2] Fragment under Mild Conditions*

Displacement of the benzene ligand in 1 surprisingly occurs more readily than that of the methyl acrylate ligand. This paves the way for 1 to undergo arene exchange and arene substitution reactions, which may be triggered by a η2→η4 haptotropic rearrangement of the acrylate. Complex 1 is thus a mild precursor of the highly unsaturated fragments [Cr(CO)2] (see scheme) and [Cr(CO)2(η2-acrylate)].