CH bond activation in functionalized organic compounds with Cp ∗ (PMe 3)IrMe(OTf): generation, structural characterization and metal-based rearrangement of the acetone activation product Cp ∗ (PMe 3)Ir(η 3-CH 2C(OH)CH 2) +OTf −

Abstract

The iridium complex Cp ∗(PMe 3)Ir(Me)OTf (1) (Cp ∗ = η 5-C 5(CH 3) 5, OTf = OSO 2CF 3) reacts cleanly with acetone at room temperature. This reaction results in overall double CH activation, generating the cationic η 3-hydroxyallyl complex Cp ∗ (PMe 3)Ir(η 3-CH 2C(OH)CH 2) +OTf − (2). Complex 2 was characterized by X-ray diffraction and found to contain a hydrogen-bonded triflate anion. The ultimate product formed on reaction with acetone is strongly dependent upon the nature of the counterion present. Replacement of the triflate ion in 2 with other anions leads to the metallacyclobutanone Cp ∗(PMe 3)Ir(η 2-CH 2COCH 2), the η 1-enolate Cp ∗( PMe 3) Ir(CH 2 COCH 3) S(p- toly) and the free cation salt Cp ∗(PMe 3)Ir(η 3-CH 2C(OH)CH 2) + B(3,5-C 6H 3(CF 3) 2) 4 −.