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Chapter 11 OChem
Ethers, Epoxides, and Sulfides
Question | Answer |
---|---|
What is an ether? | an atom of oxygen bonded to two carbon atoms. |
dimethyl ether | -two sp3 hybridized oxygens |
Alkoxy group | An -OR group, where R is an alkyl group |
ring sizes 3-6 | -irane, -etane, -olane, and -ane |
Heterocycle | a cyclic compound whose ring contains more than one kind of atom. |
Physical Ether Properties | -polar, weak dipole-dipole interactions in liquid state, boiling points are low, insoluble in water |
Preparation of Ethers | Williamson Ether Synthesis, Acid-Catalyzed Dehydration of Alcohols, Acid-Catalyzed Addition of Alcohols to Alkenes |
Williamson ether synthesis | a general method for the synthesis of diakyl ethers by an SN2 reaction between a haloalkane and an alkoxide ion. |
Ether Reactions | do not react with oxidizing agents such as potassium dichromate or potassium permanganante; stable towards stronger bases |
What do cleavage of dialkyl ethers require? | strong acid and good nucleophile |
What types of ethers are susceptible to cleavage by acid under mild conditions? | tertiary, allylic, and benzylic |
ether safety | low boiling point; highly flammable; explosive |
hydroperoxide | a compound containing an -OOH group |
protecting group | -easily added to sensitive functional group -resistant to reagents used to transform the unprotected functional group - easily removed to regenerate the original functional group |
silyl ethers | unaffected by most oxidizing and reducing agents and are stable to most nonaqueous acids and bases |
epoxides | a cyclic ether in which oxygen is one atom of a three-membered ring. |