Methods Of Aldol Condensation Methods Essay

1096 Words Apr 19th, 2016 5 Pages
The purpose of this experiment was to use aldol condensation methods to synthesize colored cyclopentadienone and then UV/VIS spectrophotometry to characterize the dienone structure synthesized. The information gathered from the UV/VIS analysis was then compared to a computer model of the desired product to analyze the optimal 3D structure of the dienone. The base catalyzed condensation reaction was used to form the product for analysis, followed by vacuum filtration to recover the product. Both a melting point analysis and a UV/VIS analysis were used to analyze the composition of the obtained product. Finally, the computer model was examined to learn about the optimal angles and strain within the molecule.
The dibenzylketone, 1,3-diphenyl-2-propanone, undergoes two consecutive base-catalyzed aldol condensations with the benzil to form the dark purple product tetraphenylcyclopentadienone. As shown in the mechanism below, the first step is the loss of an alpha hydrogen on the dibenzyl ketone to form the enolate anion. This step must occur on the dibenzyl ketone and not the benzil because the benzil does not have an alpha hydrogen to give away and therefore is incapable of making the enolate. Following the loss of the alpha hydrogen, the enolate bonds with the carbonyl carbon of the benzil and the whole compound is dehydrated. A second alpha hydrogen is removed and the compound undergoes an intramolecular cyclization, which when followed by another dehydration results in the…

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