Coupling of chiral 1-bromo-1,2-dienes with zinc-based cuprates: a new procedure for the regio and stereoselective synthesis of functionalized acetylenic compounds

Zinc alkylcyanocuprates (Knochel reagents) are found to be active in the cross-coupling reaction with allenic bromides affording acetylenic products with a high regio and stereoselective 1,3-anti substitution. The coupling process, which has been successfully extended to functionalized cuprates, can also be performed with alkylzinc chlorides in the presence of catalytic amounts of cuprous salts.