Nickel-catalyzed couplings and cyclizations involving allenes, aldehydes, and organozincs

Cyclizations of allenyl aldehydes and intermolecular couplings of allenes and aldehydes provide a direct procedure for the preparation of homoallylic alcohols. The couplings and cyclizations involve the use of diorganozinc reagents as reducing agents and Ni(COD)2 as the catalyst.