Nucleophilic Attack of Carbonyl-Stabilized Phosphorus Ylides on Neutral and Cationic Alkene Platinum(II) Complexes

The carbonyl-stabilized phosphorus ylides Ph3PCHCO2R (R = Me, Et) react with the
platinum complexes [PtCl(η2-CH2CH2)(N,N,N‘,N‘-tetramethylethylenediamine)]ClO4 and
[PtCl2(η4-diene)] (diene = 1,5-hexadiene (C6H10), dicyclopentadiene (C10H12), 4-vinylcyclohex-1-ene (C8H12), norbornadiene (C7H8)) to give complexes resulting from nucleophilic attack of
the ylide at one of the olefinic carbons. The crystal structures of [PtCl2{η3-C6H10CH(PPh3)CO2Et}], [PtCl2{η3-C10H12CH(PPh3)CO2Me}]·0.5CH2Cl2, and [PtCl2{η3-C8H12CH(PPh3)CO2Me}]·2CHCl3 are reported and indicate an exo attack in the case of the dicyclopentadiene complex
and anti-Markovnikov addition (attack at the CH2 group) in the other two complexes.