Organic Chemistry - CHEM 231A
Problem Set #2
Due Thursday, October 9 at 12:00 pm
40 points total
1. Provide names and/or structures for the following molecules: (10 pts = 2 pts each)
1e. Choose one of the above molecules and draw its enantiomer and at least two non-enantiomeric
diastereomers.
2. Consider lithium diisopropyl amide (LDA): (15 pts)
2a. diisopropyl amine has a pKa of 35. What does this mean? Explain how we
explain this number in terms of the reactivity of LDA. (2 pts)
2b. LDA is considered to be non-nucleophilic. Does this contradict the answer to 2a?
Explain. Why might it not be nucleophilic (consider the relationship between
structure and function of this molecule)? (1 pts)
2c. Consider the reaction of LDA with each of the following molecules. (9 pts = 3 pts each)
For each molecule:
a. Predict the probable product
b. If the molecule acts as an acid, identify the pKa of the acidic part.
c. If the reaction is an acid/base reaction, predict the direction the equilibrium will
lie and provide an overall reaction equilibrium constant.
HO Br
OO
2c1
2c2
2c3
OH
O
O
O
2d. Consider the molecule from question 2c3. If two mole equivalents of LDA are used, a second
reaction results in the formation of a product with the formula C
6
H
7
O
4
Li. What is the structure
of this product? Write a mechanism that accounts for the formation of this product. Why would
2 equivalents be needed for this reaction to occur? Explain. (3 pts)
NLi
+
LD
A
Br
Cl
1a.
I
1c.
1d.
(2R, 3S, 4R) 1-bromo-4-chloro-3-isopropyl-2,4,5-trimethylhexane
H
(2S, 3S, 4S, 5R, 6R) 2-bromo-3-t-butyl-5-ethyl-4-isopropyl-6-trifluoromethyloctane
1b.
