Cationic η3-allyl complexes.: 21.: Telomerization of buta-1,3-diene with Z-H compounds mediated by group 10 complexes

Cationic (eta(3)-allyl) complexes of general formula [(eta(3)-allyl)M(ligand)(2)]Y-+(-), where Y- is a non-coordinating anion (BF4-, ClO4-, BF4-) have been examined in telomerization reactions of buta-1,3-diene with representative nucleophiles. No reaction are observed for nickel complexes, due to their high reactivity versus nucleophiles. With palladium complexes, the reaction only occurs with alcohols and provides an increased selectivity for telomers with more than two diene units, leading to C-16, C-24 and even higher ethers. Although much less reactive, platinum complexes can also produce higher telomers when hydrogenosilanes are used. It is proposed, at least in the case of palladium, that the formation of C-16 and C-24 ethers arises from the coupling of C-8 units within dimeric palladium intermediates with the telogen acting as a bridging ligand. (C) 1998 Elsevier Science S.A. All rights reserved.