CHEM 322 – Spring 2015
Problem Set 1
Due 2/23/15
1. Predict the major product of the following transformation.
2. Draw the major 1,2- and 1,4-addition products of the following reaction.
3. A) In the following reaction, both the 1,2- and 1,4-addition products are observed. Please draw an arrow-pushing
mechanism that rationalizes formation of both products.
B) Explain why the ratios differ with bromine versus chlorine.
4. Assign the following molecules as aromatic, anti-aromatic, or non-aromatic and indicate the number of π electrons.
Circle your answer:
How many
Aromatic, Anti-Aromatic or Non-Aromatic
electrons in π
system?
(a)
Aromatic
Anti-Aromatic
Non-Aromatic
(b)
Aromatic
Anti-Aromatic
Non-Aromatic
(c)
Aromatic
Anti-Aromatic
Non-Aromatic
(d)
Aromatic
Anti-Aromatic
Non-Aromatic
(e)
Aromatic
Anti-Aromatic
Non-Aromatic
(f)
Aromatic
Anti-Aromatic
Non-Aromatic
5. A) Label the hybridization of each nitrogen atom in benzimidazole.
B) Is benzimidazole aromatic, anti-aromatic, or non-aromatic?
C) How many π electrons are in benzimidazole?
D) Draw a 3D representation of benzimidazole clearly showing the p-orbitals of the conjugated π system and the
orbitals that contain the nitrogen lone pairs.
6. Is cyclooctatetraene aromatic? Draw a molecular orbital diagram to rationalize your answer.
7. A) Draw an arrow-pushing mechanism for the formation of both the major and minor regioisomers of product.
H
B) For the major regioisomer, please indicate the expected stereochemistry.
C) Why is the major regioisomer favored?
8. Draw an arrow-pushing mechanism for the following reactions.
A)
B)
C)