MS 4561 - SCC CHEM 420 Dr Zenner Unit 5 Stereochemistry

MS 4561 - SCC CHEM 420 Dr Zenner Unit 5 Stereochemistry

Description: Do the even problems in Chapter 7 of 2nd Language, and the following problems.

Total Problems: 12

  1. Problem # 525

    On the molecule below, mark each stereocenter with an asterisk. (Note: in some textbooks, stereocenters are referred to as stereogenic centers, chirality centers, or asymmetric centers).

  2. Problem # 660

    Using your knowledge of 1H NMR, predict the NMR spectrum for the compound below. (draw out the spectrum you would expect to see). Be sure to include:

    • peak integrations
    • peak multiplicities
    • chemical shifts (approximate)

  3. Problem # 661

    The proton NMR of cyclohexane gives only one peak when the NMR is run at room temperature. 

    But when the temperature is lowered to -100 ºC the proton NMR spectrum shows two peaks. Explain.

  4. Problem # 526

    Assign R or S configuration for each molecule below.

    a) is straightforward. I've started you off in b).

  5. Problem # 527

    Draw the structure of (2R,3S) 2-bromo-3-chlorobutane using wedges and dashes. Also draw a Fischer projection.

  6. Problem # 528

    Indicate which of the molecules below are chiral (if any).

  7. Problem # 531


    E2 elimination reactions require anti-coplanar geometry. (note: some textbooks call this anti-periplanar).
    Let's work through an E2 reaction, and rotate the molecule eblow into an anti-coplanar geometry to predict the product of this E2 reaction.


  8. Problem # 532

    Let's work through a chiral resolution. Write out the structure of the indicated compound in each box. Include stereochemistry.

    Why is it possible to separate the (R,R) and (R,S) salts?

  9. 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.

  10. Problem # 319

    For a molecule to undergo an E2 reaction, the leaving group and the beta-proton must be in an anti-coplanar conformation (one atom straight up, the other straight down). Based on this, which compound undergoes E2 reaction with KOtBu faster? Why?


  11. Problem # 529

    Indicate the major organic product of the reaction below. Include stereochemistry.

  12. Problem # 530


    Let's work through anti and syn additions to alkenes.
    Show the product for each reaction below, and indicate whether the product will be a racemic mixture of enantiomers, or a meso compound (which is achiral).