Mixed N-heterocyclic carbene and phosphine palladium complexes for telomerization of butadiene with methanol Original Research Article

A series of hydrophilic palladium-NHC complexes have been prepared and evaluated in the telomerization of butadiene with methanol under mild conditions (50 °C) in the presence or absence of water. Palladium complexes bearing mixed NHC-phosphine or zwitterionic imidazolinium ligands exhibited high efficiency in pure methanol (TON up to 59,000). Unfortunately, they could not be used for the télomérisation of butadiene with hydrosoluble substrate as they are inactive in the presence of water. On the other hand, catalyst prepared in situ from Pd(OAc)2 and IMes.Cl was active in biphasic conditions and TON up to 10,200 was then achieved.