ON THE REQUIREMENTS OF THE PRECURSOR COMPLEX FOR OLEFIN INSERTION - REACTIVITY OF CIS-PD(C6F5)(L)2+ AND TRANS-PD(C6F5)(L)2+ WITH DIENES

The reactivity of synthons of cis- and trans-Pd(C6F5)(L)2+ towards dienes is studied. cis-Pd(C6F5)(bipy)+, which has only one coordination site available to the olefin, reacts with dienes under mild conditions to give (C6F5-allyl)palladium derivatives, suggesting that the insertion of dienes occurs on an eta2-diene complex and the second double bond is involved in allyl formation in a further step. The lack of reaction of trans-Pd(C6F5)(L)2+ under the same conditions supports experimentally earlier theoretical calculations which suggest that insertion is not favoured in a trans-M(R)(olefin) arrangement.