Quiz 10: Crossed Aldol Reaction

Question 1

What would the structure of the dehydrated product after 2 mol of benzaldehyde rxns w/ 1 mol of acetone enolate?

*See Question 1 from Quiz 10

Answer 1

II

Question 2

When performing the cross aldol rxn, it’s very important to control the stoich of the reaction. Therefore, the ketone is added in a drop-wise fashion to a stirring solution of the aldehyde in NaOH. Why can benzaldehyde or p-anisaldehyde stir in OH solution w/o forming any undesired aldol products.

A. Doesn’t contain Beta protons
B. Doesn’t contain Alpha protons
C. Doesn’t contain Beta electrons
D. Doesn’t contain Beta electrons

Answer 2

B

Question 3

When is a crossed aldol rxn said to be synthetically useful?

A. When both carbonyl compounds have alpha protons
B. When both carbonyl compounds have NO alpha protons
C. When one carbonyl compounds has NO alpha protons
D. When one carbonyl compounds has NO beta protons

Answer 3

C

Question 4

How many signals are in 13C NMR?

*See Question 4 from Quiz 10

Answer 4

8

Question 5

What is the molar equivalents of benzaldehyde is you use 365 uL benzaldehyde (D=1.044 g/mol and MW= 106.124 g/mL) and 110 uL of acetone (58.080 g/mol and D=0.791 g/mol)

Answer 5

1.2 molar eq

Question 6

Number of different aromatic signals in 1H NMR?

*See Question 6 from Quiz 10

Answer 6

3 signals

Question 7

Number of different signals in 1H NMR of product?

*See Question 7 from Quiz 10

Answer 7

6 signals

Question 8

Number of different signals in 1H NMR of product?

*See Question 8 from Quiz 10

Answer 8

5 signals

Question 9

When performing the crossed aldol rxn, it is very important to seq Q2 ethanolic NaOH. Refer to rxn below and show the structure of the product(s) that would form if all the ketone was added to the basic solution at once. Assume the products spontaneously dehydrated.

*See Question 9 from Quiz 10

Answer 9

II, III, AND IV

Question 10

Which of the following is the nucleophile?

*See Question 10 from Quiz 10

Answer 10

2