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(N)2' and S(N)2 processes giving the various doubly functionalized C(2)-symmetric allenes in good yields.