Ba(OH)2as catalyst in organic reactions, IV. Reaction between coumarin and diethyl malonate

摘要

The reaction of diethyl malonate and coumarin catalyzed by an activated barium hydroxide catalyst (C-200) in a solid-liquid-system is described. NoMichaeladdition takes place. An unusual nucleophilic addition-elimination process to the C=O bond of coumarin is observed and the new compound is described the first time. The process is explained by the microcrystalline structure of the solid, the nature of the active sites of the catalyst and the chelating action of coumarin on BaIIof the lattice.