η-Allylmetal chemistry. Part 7. Allylic alkylation catalysed by platinum complexes. Isolation of rigid (σ-allyl)(pentane-2,4-dionato)platinum(II) complexes

Abstract

Reactions of β-diketo-anions with η³-allylbis(triphenylphosphine)platinum(II) complexes or allyl acetates in the presence of triphenylphosphineplatinum complexes afford high yields of allylic alkylation products. Alkylation of the corresponding η³-but-2-enylplatinum(II) complex gives a larger amount of the product of coupling at the secondary carbon than of that at the primary carbon, while the reversed selectivity is found in the reaction of the η³-but-2-enylpalladium(II) complex. Reactions of η³-allylmono(triphenylphosphine)platinum(II) complexes with thallium(I) pentane-2,4-dionate give stereochemically rigid, thermally stable, (σ-allyl)(pentane-2,4-dionato)-platinum(II) complexes.