Influence of Base on a Surfactant‐Assisted Heterogeneous Sonogashira Reaction

Abstract We herein report a simple method for the interrogation of the influence of the bases (sodium hydroxide and various tertiary amines) on the surfactant‐assisted Sonogashira reaction utilizing a palladium on carbon catalyst. Of the bases evaluated, triethylamine (TEA) gave the best yields. The efficiency of the reaction was found to be highly dependent on surfactant concentration when using sodium hydroxide. In contrast, the reaction efficiency was found to be independent of surfactant concentration when using TEA. It was also determined that the surfactant not only facilitates the bulk transport of reactants and products within the medium, but also influences the transport and accessibility of the base to the palladium bound alkyne. The role of tertiary amines as auxiliary additives was explored in the reaction systems using NaOH as the principle base. The maximal efficiency in this case was achieved with a long‐chain tertiary amine auxiliary, N , N ‐dimethylhexadecylamine (C 16 NMe 2 ).