Preparation and NMR spectroscopy of (1,2-bis(diphenylphosphino)ethane)(eta(3)-1,3-diarylallyl)-palladium tetrafluoroborates. Correlation of chemical shifts with Hammett substituent constants and with the regioselectivity of nucleophilic attack

C-13 NMR chemical shifts of the terminal allyl carbon atoms C-1 and C-3 of (1, 2-bis(diphenylphosphino)ethane)(eta(3)-1, 3-diarylallyl)palladium tetrafluoroborates correlate with sigma Hammett substituent constants. For each complex the chemical shift at lower field indicates the site of preferred attack by soft nucleophiles in the Tsuji-Trost reaction.