Ch 13. Ether (ROR) reactions
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What are the solvent properties of ethers?
They are polar, aprotic solvents
How do you IUPAC name an ether?
use -oxy- in the name Ex. 2-ethoxypropane
How do you name crown ethers?
atoms total + crown + #oxygens
How do you get an ether from primary, secondary, tertiary and aromatic alcohols?
Williamson ether synthesis
How do you conduct Williamson ether synthesis?
• NaH • Unhindered R-X
How can you get an ether from an alkene?
Alkoxymercuration-demercuration
What reagents are needed for Alkoxymercuration-demercuration?
• Hg(OAc)2, ROH • NaBH4
How do you cleave an ether (break it up?)
By using excess HBr or excess HCl
What is an epoxide, and how does it react?
An epoxide is a three membered ring ether, and it is more reactive than other ethers because of it’s heightened ring strain
How do you name an epoxide with IUPAC method?
-substituent “epoxy” - 2 location numbers ex. 1,2-epoxyethane
What are the two routes for epoxide synthesis from an alkene?
• react with peroxy acid (CO3H) • halohydrin route
Describe the peroxy acid route that synthesizes an epoxide from an alkene.
Use a peroxy acid. RCO3H, or mCPBA, where the chlorine helps to react.
Describe the halohydrin route of epoxide synthesis.
Start with an alkene, react it with X2 (Cl,Br..) and water, to form a chlorium ion/ bromonium ion (makes chiral center, so enantiomers) and then react it with a base such as pyridine to deprotonate it , which forms the epoxide
What does pyridine look like?
It is a base, that is a benzene ring, but a Nitrogen with two lone pairs are at the bottom.
What do you get when you react an epoxide with HCl or Water or H3O+?
A 1,2-anti diol.
What do you get when you react an epoxide with H+/ in CH3OH (methanol)?
A 1,2-anti ether alcohol
What do you get when you react an epoxide with OH- in water?
A 1,2- anti diol
What do you get when you react an epoxide with: 1. OR, ROH 2. H3O+
A 1,2 anti diol
What do you get when you react an epoxide with 1. R-Li 2. H3O+
A 1,2 anti diol
In ACID CONDITIONS, what is true about the regiochemistry of the diols that are created?
The OH group on the MORE substituted C is a DASH, and the OH group on the LESS substituted C is a WEDGE
In BASE CONDITIONS, what is true about the regiochemistry of the diols that are created?
The OH group on the MORE substituted C is a WEDGE, and the OH group on the LESS substituted C is a DASH
What is another molecule that can open epoxides, that turns it into an alcohol with a RNH group on it?
Amines (Primary and secondary, but not tertiary)
What is a Thiolether?
Two R groups with a Sulfur
How do you name thiols when it is the PRIORITY group?
-thiol suffix Ex. propanethiol