Synthesis and some chemical properties of 3,3,4,4-tetraethoxybut-1-yne

Ring opening of 1,1-dibromo-2-chloro-2-diethoxymethylcyclopropane in a mixture of ethanol and dichloromethane with 50% aqueous sodium hydroxide in the presence of triethylbenzylammonium chloride (TEBA) gave 3,3,4,4-tetraethoxybut-1-yne (TEB) in excellent yield. This alkyne appears to be thermally stable at least up to 150 °C. The compound is also stable in neutral and basic aqueous solutions. In acidic aqueous media, however, TEB is unstable and was converted to one or several products depending on the reaction conditions. The most useful reaction appears to be deketalization to give 1,1-diethoxybut-3-yn-2-one, which was obtained in quantitative yield under the optimum conditions.