Testing Your Organic Chemistry Knowledge to Reinforce ...

Testing Your Organic Chemistry Knowledge to Reinforce Comprehension and
Understanding using Web-based Multiple Choice Questions
Andrew Boa and Jason Eames*
Department of Chemistry, University of Hull
a.n.boa@hull.ac.uk; j.eames@hull.ac.uk
577. Molecule Choice 34
Order the following molecules with respect to their ability to form enols:
a. A > D > B > C
*b. B > C > A > D
c. C > B > A > D
d. D > C > B > A
e. (D = A) > (B = C)
Correct Answer Reply:
During enolization the C=O bond is broken and so if there is a strong C=O bond this
process is energetically less favourable than if the bond is weaker (i.e. less enolization).
Aldehyde B > ketone C as there is only one +I methyl groups stabilizing the electron
deficient C=O in the aldehyde compared to the ketone.
Ester A > amide D has lower enol content because the lone pair on the more
electronegative oxygen is less readily delocalized into the C=O compared to the nitrogen.