Dibenzylideneacetone
Template:Chembox new 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).[1]
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.[2]
References
- ↑ Conard, C. R.; Dolliver, M. A. "Dibenzalacetone". Org. Synth., Coll. Vol. 2, p.167 (1943); Vol. 12, p.22 (1932). Article
- ↑ Rao, G. N.; Janardhana, C.; Ramanathan, V.; Rajesh, T.; Kumar, P. H. (2006). "Photochemical Dimerization of Dibenzylideneacetone. A Convenient Exercise in [2+2] Cycloaddition Using Chemical Ionization Mass Spectrometry". J. Chem. Educ. 83 (11): 1667. Unknown parameter
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