Silyl reagents (Me3Si-X) efficiently transfer X to Ir(H)2F(PtBu2Ph)2

Article abstract of DOI:10.1016/s0020-1693(97)05851-9

Me₃Si-X reagents react to completion at 25°C in a short time to convert Ir(H)₂FL₂ (L = P^tBu₂Ph) to Ir(H)₂XL₂. This involves formation of Ir-O, Ir-N, Ir-I, Ir-S and Ir-C(sp) bonds. Products include some η²-X ligands such as carboxylate and acetamide, NHC(O)CH₃. The acetamide is shown to be η² in the solid state and in solution, but readily rearranges, by a transition state with Ir-O bond cleavage, to effect site exchange of the two inequivalent hydrides. The same synthetic approach succeeds for the more crowded metallated species and these reactions are shown to fail when F is replaced by Cl in the iridium reagent. Unsaturation at Ir is suggested to be central to the mechanism of these F/X transposition reactions.