Acetoacetic Ester condensation reaction

Acetoacetic Ester can be prepared by the condensation of ethyl acetate, called the Acetoacetic Ester Condensation Reaction, a Claisen Condensation-. 

The acetoacetic ester condensation (involving the acylation of an ester by an ester) is a special case of a more general reaction term the Claisen condensation. The latter is the condensation between a carboxylic ester and an ester (or ketone or nitrile) containing an a-hydrogen atom in the presence of a base (sodium, sodium alkoxide, sodamide, sodium triphenylmethide, etc.). If R—H is the compound containing the a- or active hydrogen atom, the Claisen condensation may be written ... 

The formation of acyloins (a-hydroxyketones of the general formula RCH(OH)COR, where R is an aliphatic residue) proceeds best by reaction between finely-divided sodium (2 atoms) and esters of aliphatic acids (1 mol) in anhydrous ether or in anhydrous benzene with exclusion of oxygen salts of enediols are produced, which are converted by hydrolysis into acyloins. The yield of acetoin from ethyl acetate is low (ca. 23 per cent, in ether) owing to the accompanying acetoacetic ester condensation the latter reaction is favoured when the ester is used as the solvent. Ethyl propionate and ethyl ji-butyrate give yields of 52 per cent, of propionoin and 72 per cent, of butyroin respectively in ether. 

Acetoacetic ester condensation Amdt-Eistert reaction Bart reaction. ... 

Carboxylic esters 1 that have an a-hydrogen can undergo a condensation reaction upon treatment with a strong base to yield a /3-keto ester 2. This reaction is called the Claisen ester condensation or acetoacetic ester condensation, the corresponding intramolecular reaction is called the Dieckmann condensation ... 

Esters of dicarboxylic acids having hydrogen on the 8 or e carbon atcans undergo intramolecular cyclisation when heated with sodium or with sodium ethoxide. This cyclisation is known as the Dieckmaim reaction. It is essentially an application of the Claiseu (or acetoacetic ester) condensation to the formation of a ring system the condensation occurs internally to produce s... 

The Acetoacetic Ester Condensation and Certain Related Reactions. 

The acetoacetic ester condensation consists of a base-catalyzed reaction of two esters (at least one having an a-hydrogen atom) to form a /3-keto ester. The scope, limitations, experimental procedures, and applications have been reviewed. ... 

Hauser, C. R., Hudson, B. E., Jr. Acetoacetic ester condensation and certain related reactions. Org. React. 1942,1,266-302. 

The formation of ethyl acetoacetate is an example of a general reaction known as the acetoacetic ester condensation in which an ester having hydrogen on the a-carbon atom condenses with a second molecule of the same ester or with another ester (which may or may not have hydrogen on the a-carbon atom) in the presence of a basic catalyst (sodium, sodium etihoxide, sodamide, sodium triphenylmethide) to form a p-keto-ester. The mechanism of the reaction may be illustrated by the condensation of ethyl acetate with another molecule of ethyl acetate by means of sodium ethoxide. ... 

This reaction was first reported by Geuther in 1863 and subsequently studied by Claisen. It is a self-condensation of ester in the presence of alkali alkoxide in alcohol to form /3-keto esters (e.g. ethyl acetoacetate from ethyl acetate) and is generally known as acetoacetic ester condensation. This reaction was extensively explored by McElvain in 1930s. In general, it is carried out under basic conditions (e.g., NaOEt) to generate /3-keto-esters from aliphatic carboxylic acid esters. 

This reaction is very closely related to Acetoacetic Ester Condensation, and mechanistically, the cleavage of /3-ketoesters under strong base conditions is similar to the Retro-Aldol Addition. 

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