Reaction of η2-enone and enal-platinum(0) complexes with Lewis acidic compounds

Reaction of η2-enone and enal-platinum(0) complexes Pt(CH2CHCOR)(PPh3)2 (R=H, Me) with Lewis acidic compounds BX3 (X=F, C6F5) afforded adducts formed by coordination of boron to oxygen of the carbonyl group. The X-ray structure determination of the adduct formed from B(C6F5)3 and η2-methylvinylketone complex showed no strong interaction between Pt and carbonyl carbon. In contrast to the inability of the palladium(0) η2-enone complexes to form any Me3Al adduct, η2-cyclohexenoneplatinum(0) complex formed an isolable adduct with Me3Al, the structure of which was also confirmed by X-ray analysis. The NMR spectral parameters (Pt–C, Pt–P and P–P coupling constants) of these adducts were compared with those of the original η2-enone or enal-platinum(0) complexes as well as the ordinary η3-allylplatinum cation [Pt(PPh3)2(MeCHCHCH2)]+.