Aldol Reaction Lab Questions

Please see the attached file for the fully formatted problems.

Question 1:

In the reaction of

4-Nitrobenzaldehyde + Acetophenone  trans-4-Nitrochalcone

a. The yield of the reaction to form your chalcone is not quantitative. What side
products might be formed from your aldol condensation?

b. If one uses benzaldehyde rather than p-nitrobenzaldehyde in the aldol reaction the yield is extremely low, if it works at all. Offer an explanation for this result.

Question 2:

In the bromination of

trans-4-Nitrochalcone  erythro 2,3 dibromo 3-(4-nitrophenyl) propiophenone

a racemic mixture forms

a. Draw the structure of the enantiomers you form and assign R, and S to each of the
stereocenters.

b. Will you see 2 spots on a TLC of your reaction products? Why or why not?

c. Is your bromination reaction stereoselective? Why or why not?

Question 3:

Question 4:

When you had to form a photochromic imine you had to use ammonium bromide instead of HBr. Give 2 reasons why you cannot use concentrated HBr.

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