Dibenzylideneacetone

Dibenzylideneacetone or dibenzalacetone, often abbreviated dba, is an organic compound with the formula C17H14O. It is a bright yellow solid insoluble in water, but soluble in ethanol. Dibenzylideneacetone is used as a sunscreen component and it is used as a ligand in organometallic chemistry for instance in tris(dibenzylideneacetone)dipalladium(0). In this case, it is a labile ligand which is easily displaced by stronger ligands like triphenylphosphine, hence it serves a useful entry point into palladium(0) chemistry.

Preparation
The compound can be prepared in the laboratory by an aldol condensation of benzaldehyde and acetone with sodium hydroxide in a water / ethanol medium with the exclusive formation of the trans,trans isomer (melting point 107–111 °C).


 * [[Image:Dibenzalacetonesynth.png|500px|Dibenzalacetone synthesis]]

This reaction is frequently encountered in organic chemistry education as a laboratory procedure. The conversion proceeds via the intermediacy of benzylideneacetone.

Prolonged exposure to sunlight converts the compound in a [2+2] cycloaddition to a mixture of four cyclobutane isomers.