Reaction of arylglyoxals with acetylacetone in aqueous media: facile synthesis of 3-acetyl-1-argiopent-2-ene-1,4-dione

While for a long time water has mostly been banished from organic synthetic protocols, it has recently become popular again as a solvent for synthetic reactions in light of the search for green chemical processes. Water is a very cheap and the most environmentally benign solvent, as it is abundant in nature, and nonhazardous (inflammable, nontoxic). It also possesses a strong solvation ability especially for polar and ionic substances. In turn, this also implies that nonpolar substances, which represent the major part of reactants and products for reactions in organic synthesis, are not miscible with water and will cluster or separate to build a second liquid or solid phase. Hydrophobic reaction products can, thus, be easily separated by filtration or phase separation, while polar side products, especially saline products, are carried away with the water phase. In recent years, a surprising accelerating effect has also been observed when reactions between water-immiscible reactants were performed under stirring with water. This effect has led to the new field termed on-water chemistry [1,2]. Here we wish to report that acetylacetone react with arylglyoxals in aqueous media in the absence of any catalyst to produce 3-acetyl-1- argiopent-2-ene-1,4-dione derivatives in high yields as the only product. Reactions are clean and products are isolated as pure compounds by simple filtration.