SYNTHETIC APPLICATIONS OF ORGANOZIRCONOCENES

Alkenyl- and alkylzirconocenes are readily available by hydrozirconati on of alkynes and alkenes, respectively. Due to the relatively low nuc leophilicity of the carbon-zirconium bond in these organometallics, tr ansmetalation schemes have been developed for carbon-carbon bond forma tions. Especially, in situ transmetalation to copper(I) and zinc(II) s pecies can be used for selective alkylation reactions with organic ele ctrophiles. Alternatively, conversion of organozirconocenes to the cor responding cationic complexes enhances their reactivity considerably. Synthetic applications include protocols for orthoester formations and Diels-Alder catalysis as well as natural products (Curacin A, Manumyc in) synthesis.