BackThe Williamson ether synthesis involves the displacement of an alkyl halide or tosylate by an alkoxide ion. Would the synthesis shown be possible by making a tosylate and displacing it? If so, show the sequence of reactions. If not, explain why not and show an alternative synthesis that would be more likely to work.
Show how the following ethers might be synthesized using (1) alkoxymercuration– demercuration and (2) the Williamson synthesis. (When one of these methods cannot be used for the given ether, point out why it will not work.)
(d) 1-methoxy-1-methylcyclopentane
Draw the product of each of the following reactions:
2.
Which of the following ethers cannot be prepared by the Williamson ether synthesis?
Which of the following statements about the ether synthesis is correct regarding the preparation of unsymmetrical ethers?
Which of following ethers cannot be made by a Williamson ether synthesis?
The reaction of alkoxides with haloalkanes is not a viable way to form ethers. (a) Why? (b) Why can thioethers be formed by an analogous reaction?
Show how you would use the Williamson ether synthesis to prepare the following ethers. You may use any alcohols or phenols as your organic starting materials.
(d) ethyl n-propyl ether (two ways)
(e) benzyl tert-butyl ether (benzyl = Ph–CH2–)
Which of the following statements best describes the Williamson ether synthesis for preparing unsymmetrical ethers?
Suggest a phenoxide and an alkyl halide to make the following aryl alkyl ethers.
(a)
Predict the product when the dihydroxybenzene shown is treated with a single equivalent of both base and haloalkane.
There are two different ways of making 2-ethoxyoctane from octan-2-ol using the Williamson ether synthesis. When pure (–)-octan-2-ol of specific rotation -8.24° is treated with sodium metal and then ethyl iodide, the product is 2-ethoxyoctane with a specific rotation of -15.6°. When pure (–)-octan-2-ol is treated with tosyl chloride and pyridine and then with sodium ethoxide, the product is also 2-ethoxyoctane. Predict the rotation of the 2-ethoxyoctane made using the tosylation/sodium ethoxide procedure, and propose a detailed mechanism to support your prediction.
In Chapter 14, we saw that Agent Orange contains (2,4,5-trichlorophenoxy) acetic acid, called 2,4,5-T. This compound is synthesized by the partial reaction of 1,2,4,5-tetrachlorobenzene with sodium hydroxide, followed by reaction with sodium chloroacetate, ClCH2CO2Na.
a. Draw the structures of these compounds, and write equations for these reactions.
Both LiAlH4 and Grignard reagents react with carbonyl compounds to give alkoxide ion intermediates (that become protonated in an aqueous workup). Those alkoxides can react with 1° or methyl alkyl halides or tosylates to give ethers. Show how the following ethers can be formed in this two-step process. As starting materials you may use any reactants containing 7 carbons or fewer.
(b)
Predict the product of the following substitution/addition reactions involving phenoxides.
(a)