Arynes react with ethoxyacetylene to afford 2-ethoxyethynylaryl derivatives through a highly chemo-and regioselective formal insertion of the aryne into the C (sp)− O (sp3) bond of the alkyne. Computational studies suggest that the reaction does not proceed through a mechanism initiated by the nucleophilic addition of the oxygen atom to the aryne as previously proposed but by the addition of the triple bond of the alkyne to the aryne.
