Reaction of zirconacyclopentadienes with electrophiles such as benzaldehyde, methyl methacrylate and 1-bromo-2-butyne after treatment with RLi

Zirconacyclopentadienes reacted with electrophiles after treatment with alkyllithium. For example, the reaction with benzaldehyde after treatment with methyllithium to give a nucleophilic addition product of a dienyl moiety to aldehyde, dienylcarbinol, in a moderate yield. Similar reaction of a zirconacyclopentadiene using butyllithium with methyl methacrylate afforded a Michael addition product in a good yield. Treatment of zirconacyclopentadienes with n-BuLi followed by 1-bromo-2-butyne gave a mono-propargylated diene derivative in 95% yield after hydrolysis. When propargyl chloride was treated with n-BuLi first and then added to zirconacyclopentadienes, penta-substituted benzene derivatives were formed in high yields.