F-butyl acetoacetate

An improvement in this synthesis results from the use of the thallium salt of f-butyl acetoacetate in place of ethyl acetoacetate, and ethyl methylmalonyl chloride may replace the diacyl dihalide (75S259). 

By condensation of the dianion of f-butyl acetoacetate and (—)-menthyl (5)-p-toluenesulflnate, the corresponding 8-keto sulfoxide was obtained in high yield (eq 15) and shown to be an efficient precursor of both enantiomers of 8-hydroxybutyric acid via se-... 

Reaction with Acyl Derivatives. Enolate (1) does not react with ethyl acetate or iV,iV-dimethylacetamide, and gives a complicated mixture of products with acetyl chloride. However, (1) is acetylated with acetylimidazole to give the lithium enolate of f-butyl acetoacetate (eq 5). ... 

Cyanidiutn caldarlum) reduced aromatic ketones. Plant cell cultures (Nicotiana tabacum var. Samsun NN cells) reduced t-butyl acetoacetate to the corresponding (S)-alcohol with high optical yield. Radish (Raphanus sativus L.) sprout reduced a, a, a-trifluoro-acetophenone and Arabidopsis seedlings sprout reduced f-butyl acetoacetate to the corresponding chiral alcohol in eantiomeric excess. 

I.POXIDATION, ASYMMETRIC (--)-Benzylquininium chloride. f-Butyl hydroperoxide-Vanadyl acetoacetate. Hydrogen peroxide-1,1,3,3-Tetrachloro-aceione. (SM2-Hydroxy-N,N-diinethyl-propanamidc-OtO )oxodiperoxymolyb-denum(VI). 

Acylation, of amines with f-butyl azidoformate, 44, 17 of enamines by add halides, 43, 34 of ethyl acetoacetate by y-carbeth-oxybutyryl chloride, 42, 41 of mesitylene with oxalyl chloride, 44, 69... 

Procedure 1 Condensation of (-)-menthone and terr-butyl acetoacetate in acetic anhydrid, catalytic amount of sulphuric acid, room temperature, 24 h. The sole, previously described analogous condensation of ( -)-camphor with a-methylmalonic acid required 200 d A. Michael, N. Weiner, J. Chem. Soc. 1936, 58, 680 - 684 B. Eistert, F. Geiss, Chem. Ber. 1961, 94, 929 - 947. 

A mixture of piperidine and abs. ethanol added with stirring at —5° to n-butyraldehyde and ferf-butyl acetoacetate, stirring continued 5 hrs., then kept 44 hrs. at ca. —15°, and the crude intermediate heated at 130-140° in the presence of p-toluenesulfonic acid until a constant pressure indicates completion of the decomposition 3-hepten-2-one. Y 93%. F. e. s. S.-O. Lawesson et al., Acta Ghem. Scand. 17, 2216 (1963) C-decarbo-ferf-butoxylation with simultaneous dehydration, 2-cyclohexenones, s. R. 83, 464 (1964) reactions with ferf-butyl cyanoacetate s. Arkiv Kemi 23, 453 (1965). 

Acetoxy-2-cyclopenten-l-one in r r/-butyl acetoacetate added drop wise to a stirred soln. of K-rerr-butoxide in f rr-butyl acetoacetate, and allowed to stand overnight di-r rf-butyl 3-hydroxy-3-methyl-5,9-dioxobicyclo[5.3.0]decan-2,6-di-carboxylate. Y 88%. V. Osterthun and E. Winterfeldt, B. 110, 146 (1977). 

The butylated /J-ketoester C of Figure 13.26 is not the final synthetic target of the acetoacetic ester synthesis of methyl ketones. In that context, the /J-ketoester C is converted into the corresponding /J-ketocarhoxylic acid via acid-catalyzed hydrolysis (Figure 13.27 for the mechanism, see Figure 6.22). This /i-ketocarboxylic acid is then heated either in the same pot or after isolation to effect decarboxylation. The /f-ketocarboxylic acid decarboxylates via a cyclic six-membered transition state in which three valence electron pairs are shifted at the same time. The reaction product is an enol, which isomerizes immediately to a ketone (to phenyl methyl ketone in the specific example shown). 

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