TOPIC: 5. Nucleophilic Substitution

SUBTOPIC: 51. S_N1 Mechanism

1. Which is the most stable cation?

A. [CH₃C=CH₂] +

B. [CH₃CHCH₃}+

C. [CH₃CH₂CH₂] +

D. [HC=CHCH₃] +

____________________________________________________________

____________________________________________________________

2. Which tosylate will react most rapidly with ethanol?

____________________________________________________________

____________________________________________________________

3. Write all the resonance structures for the benzyl cation.

____________________________________________________________

____________________________________________________________

4. Write a detailed mechanism for the following reaction. Do not omit any steps. Show all intermediates and electron-pushing arrows. If the above reaction were carried out in methanol containing 0.5 M CH₃SH, would the chloride react faster, slower or at the same rate? Write the structures of all products you would expect from the reaction in the presence of CH₃SH.

____________________________________________________________

____________________________________________________________

5. Which is the most stable cation?

____________________________________________________________

____________________________________________________________

6. Write the major product(s) formed in the following reaction showing all stereoisomers in 3-D.

____________________________________________________________

____________________________________________________________

7. Write a detailed mechanism for the following transformation using electron-pushing arrows and showing all intermediates.

____________________________________________________________

____________________________________________________________

8. Give the major product(s) of the following reaction showing stereochemistry in 3-D. Indicate if the product(s) are optically active or inactive.

____________________________________________________________

____________________________________________________________

9. Which tosylate reacts most rapidly in acetic acid solvolysis?

____________________________________________________________

____________________________________________________________

10. Which is the most stable cation?

____________________________________________________________

____________________________________________________________

11. In which solvent is the S_N1 reaction the fastest?

A. diethyl ether

B. acetone

C. ethanol

D. water

____________________________________________________________

____________________________________________________________

12. Give the major product(s) of the following reaction showing stereochemistry.

____________________________________________________________

____________________________________________________________

13. Give the major product of the following reaction.

____________________________________________________________

____________________________________________________________

14. Give the major product(s) of the following reaction with stereochemistry where necessary and for each starting material and product indicate if it is chiral, achiral, optically active or racemic.

____________________________________________________________

____________________________________________________________

15. Give the major product(s) of the following reaction with stereochemistry where necessary and for each starting material and product indicate if it is chiral, achiral, optically active or racemic.

____________________________________________________________

____________________________________________________________

16. Write all the products of the following reaction showing stereochemistry in 3-D and including all stereoisomers.

____________________________________________________________

____________________________________________________________

17. Circle the alcohol which reacts the fastest with HBr.

________________________________________________________________________

18. Circle the alcohol which reacts the fastest with HBr.

________________________________________________________________________