1,4-diazabicyclo[2.2.2]octane-catalyzed self- and cross-condensation of α-acetylenic ketones

3-Butyn-2-one condenses with itself in the presence of 0.1 molar equiv of Dabco providing 80% yield of E -3-(1-buten-3-yn-2-oxy)-buten-2-one. Substitution at the acetylene terminus prevents the condensation. However, such ketones can be condensed with terminal acetylenic ketones to provide the cross-coupled products in high yields.