Cationic cyclopalladated complexes: New catalyst precursors for the telomerization of butadiene with alcohols

The cationic cyclopalladated complexes derived from N,N-dimethylbenzylamine 4, N-benzylidene-(S)-(-)-alpha-methyl-benzylamine 5 and 8-methyl quinoline 6 have been prepared and their properties as catalyst precursors for the telomerization of butadiene with methanol were investigated. The butadiene conversion was 60-70% for the three complexes and a mixture of butadiene dimers and telomers containing 2, 4 and 6 butadiene units were formed. The product selectivity is strongly influenced by the nature of the cyclopalladated complex. Thus, with complex 6 the C16 and C24 telomers were formed preferentially (more than 85%). On the other hand, with complex 4 the amount of butadiene dimers is greater than 40%. Complex 6 is also active for the telomerization of other aliphatic alcohols, but in these cases the 1- and 3-alkoxy octadiene telomers were produced preferentially.