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Chemistry LibreTexts

22.E: Carbonyl Alpha-Substitution Reactions (Exercises)

  • Page ID
    61705
  • These are the homework exercises to accompany the Textmap for McMurry's Organic Chemistry textbook.

    22.1 Keto-Enol Tautomerism

    22.1 Exercises

    Questions

    Q22.1.1

    Draw the enol forms of the following molecules

    1. 4-methylcyclohexanone
    2. Ethyl thioactetate
    3. Methyl acetate
    4. Butanal
    5. Propionic Acid
    6. 1-phenyl-2-butanone

    Q22.1.2

    How many acid protons do each of the molecules from the previous question have? Label them.

    Q22.1.3

    Draw all of the monoenol forms for the following molecule. Which ones are most stable? Why?

    Solutions

    S22.1.1

    (a)

    (b)

    (c)

    (d)

    (e)

    (f)

    S22.1.2

    (a)

    (b)

    (c)

    (d)

    (e)

    (f)

    S22.1.3

    The ability to resonate stabilizes this enol form.

    This enol has no resonance forms and is therefore less stable.

    22.3 Alpha Halogenation of Aldehydes and Ketones

    22.3 Exercises

    Questions

    Q22.3.1

    Draw out the mechanism for the following reaction.

    Q22.3.2

    How might you form 2-hepten-4-one from 4-heptanone?

    Solutions

    S22.3.1

    S22.3.2

    1) Br2, H3O+; 2) Pyridine, Heat

    22.7 Alkylation of Enolate Ions

    22.7 Exercises

    Questions

    Q22.7.1

    Propose a synthesis for each of the following molecules from this malonic ester.

    (a)

    (b)

    (c)

    Q22.7.2

    Why can't you prepare tri substituted acetic acids from a malonic ester?

    Q22.7.3

    Propose a synthesis for the following molecule via a malonic ester.

    Q22.7.4

    How might you prepare the following compounds from an alkylation reaction?

    (a)

    (b)

    (c)

    (d)

    (e)

    (f)

    Solutions

    S22.7.1

    (a) 1) Malonic Ester, NaOEt, 2) 4-Methylbenzyl Bromide, 3) Base, 4) Acid, Heat

    (b) 1) Malonic Ester, NaOEt, 2) 3-bromohexane, 3) Base, 4) Acid, Eat

    (c) 1) Malonic Ester, NaOEt, 2) 1-Bromo-2,3,3-trimethylbutane, 3) Base, 4) Acid, Heat

    S22.7.2

    Malonic esters only contain two acid protons.

    S22.7.3

    S22.7.4

    (a)

    (b)

    (c)

    (d)

    (e)

    (f)