This is part of the exam 4 review for Dr. Daoudi

1. Ch.13: Ethers, Epoxides,
Sulfides and Thiols
Oxygen, hydrogen, sulfur, sodium, and
phosphorus walk into a bar.
OH SNaP!

2. Nomenclature: Ethers
•R-O-R
•Common naming: alkyl alkyl ether
•IUPAC naming: name the ether as an alkoxy substituent off of the parent
•I Just want the IUPAC

3. Nomenclature: Epoxides
•Two ways: oxirane naming and epoxy naming
•Oxirane naming
• Include the oxygen as part of the parent
• You assign locants like it is any other ring
• The parent name is oxirane

4. Nomenclature: Thiols
•Named as thiols if they are the highest priority group
•Named as mercapto groups if they are not the highest priority group

5. Nomenclature: Sulfides
•Named pretty much the same way that ethers are named except use -alkylthio

6. Structure of ethers
•Have slightly stronger than normal van der waals
•Have weak dipole

7. Preparation of Ethers
•Williamson ether synthesis (this is by far the most important one)
•Industrial
•Alkoxymercuration-demercuration

8. Williamson Ether Synthesis
•Mechanism

9. Practice

10. Alkoxymercuration-Demercuration
Don’t worry about the mechanism
MOST IMPORTANT THING= no carbocation intermediate
But it is still Markovnikov
•THIS IS COPIED AND PASTED FROM CHAPTER 8

11. Reactions of Ethers
•Acidic cleavage
•Ether 2 alkyl halides

12. Preparation of Epoxides
•From alkenes use peroxy acids (like MCPBA)
• Don’t worry about the mech
•From halohydrins use a base
•Sharpless (I will be skipping this for today)

13. Reactions of Epoxides
•2 ways to do this
• Basic conditions (attack at less substituted side)
• Acidic conditions (attack at more substituted side)

14. Basic Conditions

15. Basic conditions: Ring-opening

16. Basic condition: Ring-opening
•Nucleophile adds to less substituted position
• Think of this reaction as an Sn2: less substituted=less sterically hindered
• and we get inversion of stereochemistry where the nucleophile attacks

17. Acid-Catalyzed Ring Opening

18. Where to add for acid-catalyzed
If there is a tertiary position then
that is where the nucleophile goes

19. Practice for ring-opening

20. Opening Up Rings
•Attack from the least substituted side
• The product should be anti periplanar
• Its just an Sn2 followed by protonation
•We can also protonate first if there is an acid catalyst
• If this is the case we attack at the more substituted side
• We attack at this side due to charge stabilization

21. practice

22. Preparation of Thiols/disuflides/sulfides
•Prepping thiols: Sn2 using –SH as a nucleophile
•Start with 2 thiolates, use base/water and Br2 disfulifde
•To make a sulfide, use a thiol and a base and then do an Sn2 w/ alkyl halide sulfide

23. Disulfide formation

24. Disulfide breaking
•HCl with Zn catalyst

25. Reactions of Sulfur Compounds