An Iterative Method for the Synthesis of Symmetric Polyynes

An iterative synthetic route for obtaining symmetric polyynes was developed, consisting of a series of iodination and Stille coupling reactions. The starting materials employed in this pathway are simple and can be prepared easily. Polyynes containing up to seven C≡C bonds were synthesized using this method. This route is particularly effective for accessing polyynes with an odd number of C≡C bonds and has allowed for the synthesis of a new iodine‐capped polyyne, diiododecapentayne.