α-Regioselective construction of gem-bisprenyl structures via zinc-mediated prenylation of esters in THF

The in situ generated prenylzinc reagent from the reaction of zinc with prenyl bromide has been shown to undergo a new type of α-regioselective addition reaction with a wide range of esters that affords gem-bisprenyl structures. The reaction proceeds under mild conditions to provide α,α′-adducts with complete α-regioselectivity. A mechanism with the consideration of the steric factors is proposed to account for the regioselective results.