Claisen-Schmidt reaction acetone

In the Claisen-Schmidt reaction, aliphatic aldehydes and ketones are the sources of the carbanion and the products are unsaturated aldehydes and ketones. In the reaction with acetaldehyde (ethanal), cinnamaldehyde (3-phenylpropenal) is formed. With acetone, 4-phenylbut-3-enone (benzyli-deneacetone) is the product (Scheme 6.18). The reaction is generally applicable and a large variety of products have been obtained in this way, some of which are used in perfumery. 

The reaction of an aldehyde with a ketone employing sodium hydroxide as the base is an example of a mixed aldol condensation reaction, the Claisen-Schmidt reaction. Dibenzalacetone is readily prepared by condensation of acetone with two equivalents of benzaldehyde. The aldehyde carbonyl is more reactive than that of the ketone and therefore reacts rapidly with the anion of the ketone to give a /3-hydroxyketone, which easily undergoes base-catalyzed dehydration. Depending on the relative quantities of the reactants, the reaction can give either mono- or dibenzalacetone. 

Similar transformations can be obtained in the reactions of acetone with aromatic aldehydes, the classic Claisen-Schmidt reaction. These reactions invariably give the a,p-unsaturated ketone products. Either the mono- or bis-condensation product may be obtained by suitable adjustment of the reaction conditions (equation 45 and 46). 46... 

The condensation of aliphatic aldehydes with acetone to give methyl vinyl ketone derivatives is rather common. The reaction can be carried out to the ketol stage (equations 39 and 40),or under conditions that lead to the a,3-unsaturated ketone (equations 41 and 42). 42 3y adjusting the stoichiometry, bis-condensation products can often be obtained in excellent yield (equations 43 and 44). 44 Similar transformations can be obtained in the reactions of acetone with aromatic aldehydes, the classic Claisen-Schmidt reaction. These reactions invariably give the a,p-unsaturated ketone products. Either the mono- or bis-condensation product may be obtained by suitable adjustment of the reaction conditions (equation 45 and 46). 46... 

Aldol and related condensation reactions such as Knoevenagel and Claisen-Schmidt condensations are also widely used in the fine chemicals and specialty chemicals, e.g. flavors and fragrances, industries. Activated hydrotalcites have been employed as solid bases in many of these syntheses. Pertinent examples include the aldol condensation of acetone and citral [107, 108], the first step in the synthesis of ionones, and the Claisen-Schmidt condensation of substituted 2-hydroxyacetophenones with substituted benzaldehydes [109], the synthetic... 

The trivial name of the reaction was applied by Wurtz in 1872, and stems from the trivial name of the dimer resulting from the acid-catalyzed self-reaction of acetaldehyde (equation 1). In time, the term came to be applied to the analogous self-condensation reactions of ketones, the first known example of which was the acid-mediated dimerization of acetone, discovered in 1838. The first use of a base as a catalyst for the aldol reaction was in the reaction of furfural with acetaldehyde or acetone (equation 2). This example also illustrates the first example of a mixed aldol reaction, a process that came to be known as the Claisen-Schmidt condensation. ... 

Dilute sodium hydroxide was used as a condensing ent by J. G. Schmidt and the method was applied by Claisen and collaborators to the s3mthesis (Claisen reaction) of aromatic ketonic esters, e.g. benzylidene acetone and di-benzylidene acetone from benzaldehyde and acetone. An alternative method was the use of an aromatic aldehyde or ketone with acetoacetic ester in presence of hydrogen chloride. Benzoylacetic ester, CgHgCO CHe-COOCoHs, was obtained by condensing benzoic and acetic esters in presence of sodium ethoxide, and j8-diketones by condensing ketones and acid esters, e.g. acetyl-acetone CHaCO-CHaCOCHg."... 

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