MS 936 - Carey and Giuliano 8th Ed. CH 20

MS 936 - Carey and Giuliano 8th Ed. CH 20

Textbook and Chapter: Carey and Giuliano 8th Ed. (2010), Chapter 20

Keywords: aldol condensation, Claisen condensation

Description: Enolate formation and carbonyl alpha position pKa.
Aldol and Claisen condensations.

Total Problems: 8

  1. Problem # 306

    Rank each group of acids in order of decreasing acidity. (1 = most acidic)

    Explain your reasoning. You will have to use more than one rule in your explanation (resonance, electronegativity, atomic radius, etc.). 


  2. Problem # 744

    After a sample of optically pure (S)-2-ethyl-cyclohexanone is dissolved in an aqueous solution for several hours, a significant loss of optical activity is observed. Explain.

  3. Problem # 745

    The molecule below has five different types of hydrogens (A through E). Rank each in order of decreasing acidity.

    (1 = most acidic). Explain your reasoning.

  4. Problem # 746

    Show what combination of aldehyde, ketone, and/or ester can prepare each compound below. Every compound is a Claisen or aldol product.

  5. Problem # 747

    Show a combination of enolate (nucleophile) and electrophile that can produce each compound below.

    Remember that all enolates come from carbonyls.

  6. Problem # 748

    Alpha bromination is usually carried out under acidic conditions via the enol intermediate. 

    Alpha bromination is uncontrollable under basic conditions, which goes through the enolate intermediate. Let's explore why.



    a) Rank each carbonyl below in order of decreasing alpha-proton acidity (1= most acidic). Explain.

    b) based on a), why does the reaction below lead to polyhalogenation?

  7. Problem # 749

    Show how to prepare each compound below from propanal. I've marked the "cuts" for you.

  8. Problem # 750

    Let's work through a Robinson annulation.

    Work backwords to determine the starting materials needed to produce each intermediate below, then show a mechanism for the overall reaction.