Download Nomenclature and Properties of Ethere and Sulfides: Synthesis and Reactions - Prof. Thomas and more Study notes Organic Chemistry in PDF only on Docsity! Chapter 14 1 1. Common names - use alkyl name + “ether” Chapter 14 2 2. IUPAC nomenclature - name the most complicated part as the alkane and add the rest as an “alkoxy” substituent (in alkyl name - drop “yl” add “oxy”). Remember the alkoxy name is only a higher priority than the halides. It is even lower than the alkyl substiuent. CH3 CH Br CH2 CH2 OCH3 1234 3-Bromo-1-methoxy-butane CH3 H H O C CH3 CH3 CH3 1 2 3 4 5 cis-3-t-butoxy-1-methyl-cyclopentane (actually the S,R enantiomer as drawn) 3. Cyclic ethers a. common names: O CH2 CH2 ethylene oxide O CH3 HH H propylene oxide Chapter 14 5 4. biological - we’ll see some more later O Et CH3 H CH2 CH2 Et H CH2 CH2 CH3 H C O OCH3 Juvenile hormone - prevents maturation of insect larvae CH H O O O CH3 CH3 Phermone for the American cockroach Chapter 14 6 5. forming complexes a. 6 electron reagents - storage b. crown ethers, etc. Chapter 14 7 CH3CH2CH2CH2 OTs + KF CH3CH2CH2CH2 F 18-crown-6 THF Chapter 14 10 2. Williamson Synthesis a. overall reaction: M (M=Na,K) R-O- M+ + R'-XR-OH (SN2 only!) (X = Cl, Br, I, OTs, etc) R-O-R' NOTE: R’X really needs to be 1° Chapter 14 11 3. Oxymercuration-demercuration a. overall reaction: 10. (8-5) Markovnikov addition H OH1) Hg(OAc)2/H2O 2) NaBH4 anti addition Markovnikov addition H OR1) Hg(OAc)2/ROH 2) NaBH4 anti addition And so using ROH in place of H2O: b. mechanism issues: Chapter 14 12 c. examples: E. Reactions of ethers - not many! 1. Cleavage by strong acids a. overall: R-O-R' + HX R-X + R'-X b. mechanism: (could be SN1 In some cases) Chapter 14 15 F. Sulfides 1. Nomenclature a. common - drop “ether” add “sulfide” b. IUPAC - replace “alkoxy” name with “alkylthio” 2. Reactions a. oxidation:
Sulfide
30% HzO.
CH,OH, NaOH
CH,COOH
50°C
ats CH;CQOQOH
a ee ee ee
1S:
Chapter 14
Chapter 14 17 b. preparation - using thiols c. reactions - substitution (SN2) Chapter 14 20 2. Reactions of epoxides - • ring strain • a. Acid catalyzed ring opening general- O H+ O H + N: N O H + (SN2 normally) The mechanism of epoxide opening in acid
Hosa H HO:
(a | HO:
protonation 20% Sy2 deprotonation +
aV_— > ™, —_—_aarc_c. + H,0:
LA Ho” (ZX 8D
5 H Hits 0H
HO: HO:
This weaker carbon—oxygen
bond will be the major bond
The general case broken by an adding nucleophile
i
Wyo WA
— | ec —cH,
eae
A specific example
£0: CH; :5H :0H
Heo HEI ed - eee
Hye ne H,G 2Cl:
(55%) (45%)
Chapter 14 21
Chapter 14 22 b. Ring opening under basic conditions: Note orientation:
epoxide
hydratase
P-450-mono-
oxygenase Ho”
Sugar Guanine
—__________ +»
P-450-mono-
oxygenase Ho™
o=6
Ps
HOw,
\
Sugar
Hg
A segment of DNA. 20H :QH 25
Chapter 14 26 H. Summary 1. Ethers a. nomenclature & spectroscopy b. preparation: i. Williamson synthesis ii. alkoxymercuration-demecuration c. reactions i. acid catalysed cleavage ii. auto-oxidation 2. Sulfides a. nomenclature b. oxidation reactions to sulfones, sulfoxides c. preparation - analog to Williamson synthesis d. sulfides as nucleophiles Chapter 14 27 3. Epoxides - synthesis a. reaction of olefins with peracids b. cyclization of halohydrins 4. Epoxides - reactions a. acid catalyzed ring opening b. nucleophilic ring opening under basic conditions
