Whittier College
Organic Chemistry: CHEM 231A
Problem Set #4
40 Points Total
Due at 12:00am on Thursday, November 20
1. Predict whether the following reactions will occur as drawn. Propose a proper product for the reaction if
it does not occur as drawn. Explain your rationale: (9 points)
1a.
1b.
1c.
Mg Br
Na2Cr2O7 / H2SO4 / H2O
O
O
Et2OO
OH
OH
OH OH OH OOH O
O
O
O
HO
H2SO4
OH O
2. Perform a retrosynthetic analysis and show the best synthesis for 1-methylcyclohexene. The starting
material may be any substituted cyclohexanone compound. Each synthetic pathway contains more than
two steps. The retrosynthetic analysis must include at least three different synthetic pathways. (11
points = 3 pts for each retro pathway, and 2 pts for depicting the best synthetic pathway)
3. Bob wanted to conduct the following reaction: (8 points)
NMR Data of Product: IR Data:
Chemical Shift: Integration: Coupling: Main peaks:
0.91 ppm 18 mm triplet 3545 – 3275 cm-1 (Strong, Broad)
1.22 ppm 11 mm quintet 1175 cm –1 (strong)
1.25 ppm 12 mm doublet GC-MSD Data:
1.78 ppm 6 mm sextet 1 main peak in Chromatogram
3.81 ppm 3 mm triplet molecular ion m/z = 142
3a. Based on the experimental data, did he succeed? If not, what product did he form? Explain briefly. (5
points).
3b. After Bob obtained his product from problem 3, he decided he wanted to recrystalize the oil he had. He
decided to use dissolve his product in 6 M H2SO4. What do you think would happen to his product? (3
pts). Show a mechanism for your predicted product (s).
H
O
1. Mg / Et2O
2. 4-methyl Benzaldehyde / Et2O
H
O
Br
OH
