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Claisen condensations and enolate acylation

17 real reactions from the literature: Claisen condensation on esters and five-membered cyclic ketones; Dieckmann on esters; enolate C-acylation on aryl ketones, six-membered cyclic ketones and methyl ketones. Each scheme shows starting materials, conditions and products, with the yield and reference where the source reports them.

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  1. Claisen condensation: ethyl 4-(3-oxocyclohexyl)butanoate (an ester) with tBuOK; THF gives hexahydro-1,8(2H,5H)-naphthalenedione (the 1,3-diketone). 65% yield.
    Claisen condensationSynlett 2006, 309

  2. Dieckmann: diethyl 3,3-dibutylhexanedioate (an ester) with 1) NaH; 2) HCl gives 3,3-dibutylcyclopentanone (the cyclic β-keto ester). 85% yield.
    DieckmannJ. Org. Chem. 1994, 59, 5496

  3. Enolate C-acylation: propionyl chloride (an acid chloride) and cyclohexanone (a six-membered cyclic ketone) with TsOH; EtOH gives 2-propanoylcyclohexan-1-one (the 1,3-diketone). 85% yield.
    Enolate C-acylationChem. Ber. 1957, 90, 2833

  4. Claisen condensation: acetone (a methyl ketone) and ethyl acetate (an ester) with 1) Na, CH3CH2OH; CH3CH2OCH2CH3; 2) H2SO4 gives acetylacetone (the 1,3-diketone).
    Claisen condensationOrg. Synth. Coll. Vol. 3, p. 17

  5. Dieckmann: dimethyl 4-propan-2-ylideneheptanedioate (an ester) with NaH, DME gives methyl 2-oxo-5-(propan-2-ylidene)cyclohexanecarboxylate (the cyclic β-keto ester).
    DieckmannChem. Commun. 1967, 753

  6. Enolate C-acylation: phthalimidoacetone (a methyl ketone) with NaOMe gives 3-acetyl-2,3-dihydroisoquinoline-1,4-dione (the 1,3-diketone).
    Enolate C-acylationRealOChem worksheet

  7. Claisen condensation: acetophenone (an aryl ketone) and ethyl benzoate (an ester) with 1) NaOCH2CH3, Δ; 2) aq. H2SO4 gives dibenzoylmethane (the 1,3-diketone).
    Claisen condensationOrg. Synth. Coll. Vol. 3, p. 251

  8. Dieckmann: an ester with 1) LiHMDS; 2) HCl workup gives the cyclic β-keto ester. 89% yield.
    DieckmannEur. J. Org. Chem. 2000, 2605

  9. Enolate C-acylation: an aryl ketone and dimethyl oxalate (an ester) with NaH, DMF, MeOH (same reactants as K) gives the 1,3-dicarbonyl compound. 60% yield.
    Enolate C-acylationJ. Am. Chem. Soc. 1968, 90, 439

  10. Claisen condensation: ethyl benzoate (an ester) and ethyl acetoacetate (a β-keto ester) with 1) Na, CH3CH2OH, Δ; 2) H2SO4, H2O gives ethyl benzoylacetate (the β-keto ester).
    Claisen condensationOrg. Synth. Coll. Vol. 3, p. 379

  11. Dieckmann: an ester with 1) NaOEt, EtOH, 3 h / reflux; 2) cool to 0 C, add MeI gives the cyclic β-keto ester. 68% yield.
    DieckmannJ. Chem. Soc. 1960, 2842

  12. Enolate C-acylation: an aryl ketone and dimethyl oxalate (an ester) with NaH, DMF, MeOH gives the 1,3-dicarbonyl compound. 45% yield.
    Enolate C-acylationJ. Am. Chem. Soc. 1968, 90, 439

  13. Claisen condensation: a five-membered cyclic ketone with HCO2Et; NaH; THF gives the β-keto carbonyl compound. 83% yield.
    Claisen condensationJ. Am. Chem. Soc. 1979, 101, 6765

  14. Claisen condensation: ethyl 2-methyl-1,3-oxazole-4-carboxylate (an ester) with NaH; EtOAc gives the β-keto ester. 26% yield.
    Claisen condensationJ. Org. Chem. 1982, 47, 2999

  15. Claisen condensation: ethyl 2'-acetyl[1,1'-biphenyl]-2-carboxylate (an ester) with NaOEt gives the β-keto carbonyl compound. 85% yield.
    Claisen condensationChem. Ber. 1971, 104, 1573

  16. Claisen condensation: ethyl 2-phenoxyacetate (an ester) with 1) LiN(SiMe3)2; 2) gives the β-keto ester. 39% yield.
    Claisen condensationEur. J. Med. Chem. 2009, 44, 3852

  17. Claisen condensation: methyl 5,5-dimethoxyvalerate (an ester) with NaH, DME gives the β-keto ester. 68% yield.
    Claisen condensationJ. Am. Chem. Soc. 1979, 101, 7032