addition) reaction as shown below: me OH ÓH Ph Warfarin a) Propose a mechanism for the reaction starting from the enolate shown below. You can assume water is present for any proton transfers needed. Ph :0:
Reactions of Ethers
Ethers (R-O-R’) are compounds formed by replacing hydrogen atoms of an alcohol (R-OH compound) or a phenol (C6H5OH) by an aryl/ acyl group (functional group after removing single hydrogen from an aromatic ring). In this section, reaction, preparation and behavior of ethers are discussed in the context of organic chemistry.
Epoxides
Epoxides are a special class of cyclic ethers which are an important functional group in organic chemistry and generate reactive centers due to their unusual high reactivity. Due to their high reactivity, epoxides are considered to be toxic and mutagenic.
Williamson Ether Synthesis
An organic reaction in which an organohalide and a deprotonated alcohol forms ether is known as Williamson ether synthesis. Alexander Williamson developed the Williamson ether synthesis in 1850. The formation of ether in this synthesis is an SN2 reaction.
![6. The anticoagulant Warfarin can be synthesized by a conjugate addition (Michael
addition) reaction as shown below:
Ph
ОН
ОН Ph
Warfarin
a) Propose a mechanism for the reaction starting from the enolate shown below. You can
assume water is present for any proton transfers needed.
Ph
:0:
b) We saw that the keto tautomer is normally preferred over the enol tautomer, however,
the enol tautomer is present in the final product (Warfarin) and that is the more stable
tautomer in this case. Why do you think the enol tautomer is more stable? Hint: consider
the molecule as a whole.
Ph
ОН Ph
keto tautomer
enol tautomer
5](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6634c597-bcb3-43b8-9fcc-3e556f1bdb31%2Fd966129c-00b9-4428-abc8-1015a39f1b7e%2Fio9w6ca_processed.jpeg&w=3840&q=75)
![4. The following enolate alkylation reaction is attempted in the laboratory as shown:
1. NaOH
2. CH3BR
desired product
The 'H NMR shown below was taken after the reaction.
6H
3H
2H
1H
6.
4
3
1
PPM
a) Does the NMR shown above match the desired product? How could
you
tell?
b) Use a mechanism to show how the product that matches the NMR above is formed
under the given conditions.
c) Suggest an alternate (or better) way to perform the reaction to obtain the desired
product above. Be sure to give a specific example of the conditions.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6634c597-bcb3-43b8-9fcc-3e556f1bdb31%2Fd966129c-00b9-4428-abc8-1015a39f1b7e%2F3p1u7lc_processed.jpeg&w=3840&q=75)
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