1. EthersR-O-R or R-O-R´ Nomenclature: simple ethers are named: “alkyl alkyl ether” “dialkyl ether” if symmetric CH 3 CH 3 CH 3 CH 2 -O-CH 2 CH 3 CH 3 CH-O-CHCH 3 diethyl ether diisopropyl ether

2. CH 3 -O-C(CH 3 ) 3 tert-butyl methyl ether (MTBE) If complex, the ether part is named as an “alkoxy” group: CH 3 -O- = methoxy CH 3 CH 2 -O- = ethoxy, etc. CH 3 -O-CH 2 CH 2 CH 2 -O-CH 3 1,3-dimethoxypropane HO-CH 2 CH 2 -O-CH 2 CH 3 2-ethoxyethanol

3. Physical properties: oxygen is sp 3 hybridized, bond angle ~ 109.5 o ethers are polar; no hydrogen bonding mp/bp moderate water insoluble Diethyl ether = very important organic solvent, polar, water insoluble, bp = 35 o. Very flammable & forms explosive peroxides.

4. Industrial synthesis for diethyl ether: 2 CH 3 CH 2 -OH + H 2 SO 4, 140 o C  CH 3 CH 2 -O-CH 2 CH 3 + H 2 O Not generally useful for syntheses of ethers in the lab: a)Only symmetric ethers can be made this way. b)Conditions are very compound specific ( at 180 o ethanol would yield ethylene instead of the ether)

5. Synthesis of ethers 1.Williamson Synthesis. R-O - Na + + R´-X  R-O-R´ + NaX  R´-X should be CH 3 or 1 o S N 2 mechanism

6. Mechanism for the Williamson Synthesis = S N 2 R´-X should be CH 3 or 1 o

7. R-OH + Na  R-O - Na +  R-O-R´ R´-OH + HX  R´-X (CH 3 ) 2 CH-OH + Na  (CH 3 ) 2 CH-O - Na + +  CH 3 CH 2 CH 2 -O-CH(CH 3 ) 2 CH 3 CH 2 CH 2 -OH + HBr  CH 3 CH 2 CH 2 -Br isopropyl n-propyl ether note: the alkyl halide is primary!

8. CH 3 CH 2 CH 2 -OH + Na  CH 3 CH 2 CH 2 -ONa +  CH 3 CH 2 CH 2 -O-CH(CH 3 ) 2 (CH 3 ) 2 CH-OH + HBr  (CH 3 ) 2 CH-Br 2 o  alkene The product of this attempted Williamson Synthesis using a secondary alkyl halide results not in the desired ether but in an alkene! The alkyl halide in a Williamson Synthesis must beCH 3 or 1 o ! 

9. Synthesis of di-tert-butyl ether? CH 3 CH 3 CH 3 C-O-CCH 3 Cannot be made via the Williamson CH 3 CH 3 Synthesis. The alkyl halide would be 3 o. 2.Alkoxymercuration-demercuration A way to make ethers that cannot be made via the Williamson Synthesis. (later)

10. Acids Bases Metals Oxid. Reduc. Halogens NR     some NR     R-H R-X R-OH R-O-R

11. Reactions, ethers: 1.Acid cleavage. R-O-R´ + (conc) HX, heat  R-X + R´-X CH 3 CH 2 -O-CH 2 CH 3 + HBr, heat  2 CH 3 CH 2 -Br

12. SN2SN2 SN2SN2

13. Alkanes Nomenclature Syntheses 1. 2. reduction of an alkyl halide a) hydrolysis of a Grignard reagent b) with an active metal and acid 3. Corey-House Synthesis Reactions 1. halogenation 2. combustion (oxidation) 3. pyrolysis (cracking)

14. Alkyl halides: nomenclature syntheses: 1. from alcohols a) HX b) PX 3 2. halogenation of certain alkanes 3. 4. 5. halide exchange for iodide reactions: 1. nucleophilic substitution 2. 3. formation of Grignard reagent 4. reduction

15. Alcohols: nomenclature syntheses later reactions 1. HX 2. PX 3 3. 4. as acids 5. ester formation 6. oxidation

16. Ethers nomenclature syntheses 1. Williamson Synthesis 2. reactions 1. acid cleavage

17. Mechanisms: Free radical substitution S N 2 S N 1 Memorize (all steps, curved arrow formalism, RDS) and know which reactions go by these mechanisms!