In situ generated half-lanthanidocene based catalysts for the controlled oligomerisation of styrene: Selectivity, block copolymerisation and chain transfer

The Cp∗Nd(BH4)2(THF)2/n-butylethylmagnesium combination affords a controlled and syndioselective oligomerisation of styrene. Living oligostyrenes can be used as macromonomers for block copolymerisation, leading to the unprecedented synthesis of a (polystyrene)-block-(1,4-trans polyisoprene) copolymer. Reversible transmetallation between the neodymium and the magnesium atom is further established with a transfer efficiency close to 100%.