Exam 3 Summer 2011
Name______Seat Number______
Student ID______
The exam consists of 7 questions on a total of 9 pages, including bond dissociation energies and periodic table. The exam will be graded out of 100 points
- _____/10
- _____/24
- _____/12
- _____/12
- _____/12
- _____/20
- _____/10
Regrading: All requests for regrades must be submitted in writing within 48 hours of the return of the exam. You must explicitly state what has been misgraded and why it is an error. The entire exam will be regraded, which could result in points being added or deducted overall.
1. (10pts) 3-chloro-1-butene reacts with sodium ethoxide in ethanol to produce 3-ethoxy-1-butene. The reaction is second order, first order in 3-chloro-1-butene, and first order in sodium ethoxide. In the absence ofethoxide, the reaction produces 3-ethoxy-1-butene and 1-ethoxy-2-butene. Explain these results using mechanisms as part of your explanation.
2. (24pts) Draw the major product(s) of each reaction and specify the most likely mechanism(s) by which it(they) i/are formed ( SN1, SN2, E1, E2, or more than one of these.)
3. (12pts) In the elimination drawn below, only one product forms. Indicate which product forms, then draw an arrow mechanism that indicates how this product formed. (Include proper conformations of all reactants.)
If the same reaction is carried out in water, would the major product be the same or different than the product of the reaction above? Explain why.
4. (12pts) Provide reagents.
5. (12pts) Provide a mechanism for this dehydration. In what order are the two alcohols most likely to dehydrate?
6. (20pts) Draw the rate determining propagation step for this radical halogenation, and calculate the change in energy for this step. (See attached tables and show work.)
Draw the rate determining propagation step for this radical halogenation, and calculate the change in energy for this step. (See attached tables and show work.)
Which product, 1-chlorobutane or 2-chlorobutane, would you expect to be the major product? Explain why it is favored using an appropriate energy diagram.
Why is chlorination less selective than bromination? Be sure to refer to the Hammond postulate in your answer.
7. (10pts) One of these reaction sequences works well to produce this ether; the other does not. For the reaction that works, provide a mechanism. For the reaction that does not work, explain why it does not produce the given product.