Enyne Meldrum′s acid derivatives: synthesis and Michael reactions with amines and thiols

The Knoevenagel condensation of arylpropynals with Meldrum ' s acid in the presence of Et3N affords 5-(3-arylprop-2-yn-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-diones in 58-77% yields. Amines and thiols readily add to the resulting products at the triple bond giving the corresponding allylidene derivatives. In the Michael nucleophilic addition, the triple bond in enyne derivatives is much more active compared to that in 1,5-diarylpent-2-en-4-yn-1-ones. The three-component synthesis based on Meldrum ' s acid, arylpropynals, and amines or thiols affords allylidene derivatives in 71-96% yields.