Insertion of lithium chloropropargylide or lithium chloroallylide into bicycliczirconacyclopentanes gives 1-zirconacyclooct-3-ynes or -3-enes respectively. The former give allenes on protonolysis. The latter react further with ketones or aldehydes to afford 1-zircona-2-oxa-5-decenes which give (E)-homoallyic alcohols on aqueous work-up. With aldehydes moderate 1,6-diastereocontrol is observed.