Formation of Osmium-Allylphosphinomethanide Complexes by Coupling of an Isopropenyldiisopropylphosphine and Monosubstituted Allenes

Complex [Os(η5-C5H5){κ3-P,C,C-PiPr2[C(Me)═CH2]}(MeCN)]PF6 (1) reacts with cyclohexylallene and ethyl carboxylate allene to give the allylphosphinomethanide derivatives [Os(η5-C5H5){κ5-P,Ca,Cb,Cc,Cd-PiPr2[Ca(Me)CH2Cb(CcH2)CdHR]}]PF6 (R = Cy (2), CO2Et (3)). In fluorobenzene at 95 °C, complexes 2 and 3 evolve into the corresponding γ-allyl-α-alkenyldiisopropylphosphine compounds [OsH(η5-C5H5){κ4-P,Ca,Cb,Cc-PiPr2[C(═CH2)CH2Ca(CbH2)CcHR]}]PF6 (R = Cy (4), CO2Et (5)). Complexes 2 and 4 have been characterized by X-ray diffraction analysis.
Financial support from the Spanish MICINN (Projects CTQ2011-23459 and Consolider Ingenio 2010 (CSD2007- 00006)), the Diputación General de Aragón (E35), and the European Social Fund is acknowledged.