Alkenyl-Assisted C3–C Bond Activation of Acetylacetonate Coordinated to Iridium

The cleavage of a C3–C bond of the acetylacetonate (acac) ligand of the complexes Ir­{(E)-CHCHR}­{κ2 -N,C-(quin-C6H4)}­(acac)­(P i Pr3) (R = H (1), Ph (2)) has been achieved by reaction with an acid and subsequently with a base. The rupture is assisted by the alkenyl coligand. The latter reacts with the acid to be coupled with the acac group, in order to weaken the C3–C bonds. Then, the base removes an acylium group from the resulting intermediates [Ir­{κ2 -N,C-(quin-C6H4)}­{κ3 -O,O,C-(acac-C2H2R)}­(P i Pr3)]+ (R = H (3), Ph (4)) to afford Ir­{κ2 -N,C-(quin-C6H4)}­{η4-CH­(R)­CHC­(Me)­O}­(P i Pr3) (R = H (5), Ph (6)).