Organic Chemistry II
Professor Carl C. Wamser
Chapter 14 Workshop
1. Compounds A and B both have a molecular formula of C7H7Br. When either is reacted with Mg/Et2O followed by treatment with H2O, toluene (C6H5CH3) is obtained. When A is added to AgNO3/EtOH, an immediate precipitate occurs. However, when B is added to AgNO3/EtOH, even heating for extended periods of time yields no precipitate. Give possible structures for A and B, and explain the reasoning behind your assignments.
2. Methyl formate reacts with two equivalents of ethyl magnesium bromide. Give the structure of the final product, C5H12O, isolated after work up. Give a mechanism for the formation of this product.
3. a. Disconnect the following alcohol to all of the possible combinations of Grignard reagents and carbonyl reactants.
b. Construct a retrosynthetic tree for the synthesis of ethylcyclohexane from cyclohexane. Include as many routes (branches) as possible. Evaluate the efficiency of each step in each route. Come to a group consensus about the most efficient route.
4. Develop synthetic routes that would start with toluene and prepare either p-chlorobenzoic acid or m-chloropbenzoic acid.
5. Benzyl bromide undergoes rapid SN1 reaction in methanol solvent. p-Aminobenzyl bromide reacts even faster in methanol. Write a complete mechanism, including all resonance forms. Explain the effect of the amino substituent.
Materials adapted from:
Peer-Led Team Learning: Organic Chemistry, 1/e
Jack A. Kampmeier, University of Rochester
Pratibha Varma-Nelson, St. Xavier University
Donald Wedegaertner, University of the Pacific
Prentice-Hall, 2001, ISBN 0-13-028413-0