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ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
CONCEPT: ETHER NOMENCLATURE
□ Common Name: List alkyl groups in alphabetical order and follow with the word ____________
□ IUPAC: Smaller half of the ether is named as an _________________ substituent on the main alkane chain
EXAMPLE: Provide the correct common and IUPAC name of the following ether
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 2
CONCEPT: EPOXIDE NOMENCLATURE
□ Cyclic ethers are named as a unique functional group due to increased reactivity.
● 3-membered ethers are called _________________ or ___________________
□ Cycloalkane Convention: Name the ring as a cycloalkane, adding the prefix ________ and location if necessary
□ Epoxy Convention: Name as a di-located substituent on the longest carbon chain
□ Oxide Convention: Name as an alkene, followed by the word ___________
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 3
PRACTICE: Provide ALL the names applicable for the following molecule
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 4
PRACTICE: Provide ALL the names applicable for the following molecule
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 5
CONCEPT: SULFUR NOMENCLATURE
□ Sulfur is similar to oxygen in its atomic composition, so it forms oxygen compound analogs.
● Alcohol has higher priority than thiols
EXAMPLE: Provide the IUPAC names (and common names if appropriate) for the following compounds.
a.
b.
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 6
CONCEPT: SYNTHESIS OF ETHERS
1. Williamson Ether Synthesis (SN2 of 1o or 0o RX)
● Substitution with an oxide base. 2o and 3o alkyl halides will favor _______
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 7
2. Acid-Catalyzed Alcohol Condensation
● Only forms _______________________________ ethers.
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 8
CONCEPT: SYNTHESIS OF ETHERS
3. Alkoxymercuration of alkenes
● Same mechanism as oxymercuration, but using _________________ as the nucleophile instead of H2O.
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 9
4. Acid-Catalyzed Alkoxyation
● Same mechanism as acid-catalyzed hydration, but using ______________ as the nucleophile instead of H2O
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 10
PRACTICE: Predict the product for the following reaction
PRACTICE: Predict the product for the following reaction
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 11
CONCEPT: CLEAVAGE OF ETHERS
□ Ethers are very combustible, but unreactive. They contain two strong C—O bonds that are not easy to break.
● They only undergo one synthetically useful reaction: cleavage in the presence of strong acid.
Mechanism:
EXAMPLE: Predict the product of the following reaction
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 12
CONCEPT: TERT-BUTYL ETHER PROTECTING GROUPS
□ Protecting groups are used to shield reactive moieties while reactions are happening on other parts of the molecule.
● By definition, they must be completely reversible.
EXAMPLE: Will the following reaction proceed efficiently as drawn? Why or why not?
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 13
t-Butyl Ether: ● Addition of isobutylene through reversible acid-catalyzed alkoxylation
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 14
CONCEPT: SILYL ETHER PROTECTING GROUPS
□ A group used to protect alcohols are silyl (silicon) chlorides.
Mechanism: ● TBDMS is the most common silyl chloride in Organic Chemistry 1
EXAMPLE: Predict the product of the following reaction
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 15
CONCEPT: EPOXIDATION
□ Epoxides are added to double bonds using _________________ ____________
● Common reagents are _____________ and ___________
Mechanism:
□ Epoxides can also be generated though an intramolecular _______ reaction of halohydrins.
Mechanism:
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 16
CONCEPT: EPOXIDE RING OPENING
1. Acid-Catalyzed Ring Opening
Following protonation of the epoxide, the nucleophile will attack the side of the ring with the most ___________ character:
2. Base-Catalyzed Ring Opening
The strong nucleophile will attack the side of the ring that is ___________ substituted
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 17
CONCEPT: SHARPLESS ASYMMETRIC EPOXIDATION
□ Enantioselective reactions are ones that generate _____ enantiomer in significantly higher yield than another.
□ Converts allyl alcohols into enantioselective epoxides depending on the tartrate used (+) or (-).
General Reaction:
□ Always draw alcohol on the ____________ __________ corner of the double bond. Then determine chirality using DET.
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 18
CONCEPT: REACTIONS OF THIOLS
□ Thiols contain an _____________ hydrogen, so they become excellent nucleophiles after exposed to __________
● These nucleophiles are called __________________
Sulfide Synthesis:
Disulfide Synthesis:
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 19
CONCEPT: OXIDATION OF SULFIDES
□ Oxidation reactions involve an increase in the ______________ content of a molecule
□ Sulfides are more reactive than ethers because it has an expanded octet and can form additional bonds with other atoms.
● They are particularly susceptible to oxidation.
ORGANIC - KLEIN 3E
CH.13 - ETHERS AND EPOXIDES; THIOLS AND SULFIDES
Page 20
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