Short and easily scalable synthesis of the sex pheromone of the horsechestnut leaf miner (Cameraria ohridella) relying on a key ligand and additive-free iron-catalyzed cross-coupling

We describe in this work a short 6-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 with a high yield in the absence of additional ligands or additives. DFT calculations moreover suggest that ω-alkoxide groups on iron-ligated chains in transient organoiron(II) intermediates can enhance their stability and hamper their decomposition in off-cycle β-hydride elimination reactions.