Hexadehydro Diels–Alder/Alkynyliodanation Cascade: A Highly Regioselective Entry to Polycyclic Aromatics

We report here a cascade process integrating the hexadehydro Diels-Alder (HDDA) reaction with alkynyliodanation, enabling efficient synthesis of highly substituted aryl-λ³-iodanes. Heating a mixture of a tetrayne and an alkynylbenziodoxole induces regioselective insertion of the tetrayne-derived aryne into the alkynyl-iodine(III) bond, yielding a 1,4-dialkynyl-2-iodanyl-3-aryl(or alkyl)benzene derivative. The unique regiochemistry facilitates subsequent π-extension, allowing divergent access to polyaromatic frameworks, such as helicenes and cyclopenta[<i>cd</i>]pyrenes, underscoring the utility of aryne carboiodanation in complex aromatic synthesis.