Asymmetric activation of dialkyl zirconocenes

Asymmetric alkylmethyl zirconocene derivatives were readily synthesised from Cp2ZrCl(CH3), and the appropriate alkyllithium reagent. The alkyl groups contain a silyl functionality on the β-position. These asymmetric dialkyl zirconocenes were successfully activated by B(C6F5)3, selectively abstracting the methyl group. The clear difference in the 13C NMR resonances, due to the alkyl groups on the cationic zirconocene made it possible to conclude that selective activation of this class of compounds was possible.