A new and efficient route for 1,3,3′-triketones

Cyclic and acyclic 1,3,3′-triketones were prepared by the reactions adopting β-diketones and anhydrides in the presence of barium or strontium hydrides in high yields. Crystal structure of 4-acetyl-2,2,6,6-tetramethyl-3,5-heptanedione (3a) represented the dorminant keto form and provided evidence for intermolecular CH⋯O hydrogen bonds (average C⋯O distance; 3.437 Å, average CH⋯O angle; 169.25°).