A Versatile Hexadiene Synthesis by Decarboxylative sp³–sp³ Coupling/Cope Rearrangement

Have it both ways: The palladium-catalyzed decarboxylative coupling of esters with two allyl groups results in kinetic allylation at a position α to electron-withdrawing groups. Tandem allylation/Cope rearrangement provides access to γ-coupling products (see scheme). Thus, the desired regioisomer is obtained simply by controlling the temperature of the reaction mixture.