Preparation of C₂-Symmetric Allenes by Palladium-Catalyzed Double-Nucleophilic Substitution on 3-Bromopenta-2,4-dienyl Acetate

Easily accessible 3-bromopenta-2,4-dienyl acetate was applied to the palladium-catalyzed reaction with soft nucleophiles. The reaction proceeded through the stepwise 2-fold nucleophilic substitution via formal S_N2′ and S_N2 processes giving the various doubly functionalized C₂-symmetric allenes in good yields.