Short and Easily Scalable Synthesis of the Sex Pheromone of the Horse-Chestnut Leaf Miner (Cameraria ohridella) Relying on a Key Ligand- and Additive-Free Iron-Catalyzed Cross-Coupling

We describe in this work a short six-step convergent high-scale synthesis of the sex pheromone of the horse-chestnut leaf miner ((8E,10Z)-tetradeca-8,10-dienal). This procedure relies on a key stereoselective iron-catalyzed Kumada cross-coupling, which affords the coupling product in high yield in the absence of additional ligands or additives. DFT calculations moreover suggest that co-alkoxide groups on iron-ligated chains in transient organoiron(II) intermediates can enhance their stability and hamper their decomposition in off-cycle beta-hydride elimination reactions.