Acetoacetic ester synthesis dialkylation

Among other methods for the preparation of alkylated ketones are (1) the Stork enamine reaction (12-18), (2) the acetoacetic ester synthesis (10-104), (3) alkylation of p-keto sulfones or sulfoxides (10-104), (4) acylation of CH3SOCH2 followed by reductive cleavage (10-119), (5) treatment of a-halo ketones with lithium dialkyl-copper reagents (10-94), and (6) treatment of a-halo ketones with trialkylboranes (10-109). 

Controlled, stepwise dialkylation may be performed as exemplified in equation 73, which shows a typical malonic ester synthesis including hydrolysis and decarboxylation to give an a,a-dialkylated acid. Acetoacetic ester synthesis and cyanoacetic ester syntheses give ketones (CH3COCHRR ) and nitriles (RR CHCN), respectively. 

On heating with aqueous HCl, the alkylated (or dialkylated) acetoacetic ester is hydrolyzed to a jCJ-keto acid and then decarboxylated to yield the ketone product. The decarboxylation occurs in the same way as in the malonic ester synthesis and involves a ketone enol as initial product. 

Notice the similarity to the malonic ester synthesis. Ethyl acetoacetate is the starting material. It is first deprotonated, then treated with an alkyl halide, and then treated with aqueous acid at elevated temperature. Ethyl acetoacetate can also be dialkylated to produce ketones as follows ... 

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