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प्रश्न
Illustrate with examples the limitations of Williamson synthesis for the preparation of certain types of ethers.
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उत्तर
The main limitation of Williamson's ether synthesis is that it cannot be used to prepare unsymmetrical ethers where the compound has tertiary or secondary alkyl groups. For example, a reaction between tert-butyl bromide and sodium methoxide yields an alkene.
\[\begin{array}{cc}
\ce{CH3}\phantom{..........................}\ce{CH2}\phantom{.........}\\
\phantom{.}|\phantom{..............................}||\phantom{............}\\
\ce{CH3 - C - Br + NaOCH3 -> CH3 - C + NaBr + CH3OH}\\
|\phantom{..............................}|\phantom{............}\\
\ce{\underset{tert-Butylbromide}{CH3}\phantom{..................}\ce{\underset{2-Methylpropene}{CH3}}}\phantom{..........}\
\end{array}\]
This is due to the formation of alkene and the dominance of the competing elimination reaction over SN2.
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संबंधित प्रश्न
Explain the mechanism of the following reaction:
How do you convert the following :
Phenol to anisole
Write the name of the reagent and the equation for the preparation of the following ether by Williamson’s synthesis:
1-Propoxypropane
Write the name of the reagent and equation for the preparation of the following ethers by Williamson’s synthesis:
1-Methoxyethane
Explain the following with an example.
Williamson ether synthesis
Account for the following :
t-butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butyl methyl ether.
\[\ce{(CH3)3CONa + CH3CH2Cl ->[-NaCl] (CH3)3COC2H5}\] is called:
Which of the following compounds gives a secondary alcohol upon reaction with methylmagnesium bromide?
HBr reacts with \[\ce{CH2 = CH - OCH3}\] under anhydrous conditions at room temperature to give ______.
Write the name of the reaction, structure and IUPAC name of the product formed when:
\[\ce{CH3CH2CH(CH3)CH(CH3) ONa}\] reacts with \[\ce{C2H5Br}\]
Write the name of reagent and equation for the preparation of the following ethers by Williamson’s synthesis:
2-Methoxy-2-methylpropane
What is metamerism? Give the structure and IUPAC name of metamers of 2-methoxy propane.
Write the name of reagents and equations for the preparation of the following ethers by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Write the name of reagent and equation for the preparation of the following ethers by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Short Answer Question.
Identify the product (s) is / are formed when 1 – methoxy propane is heated with excess HI. Name the mechanism involved in the reaction
Write the names of reagents and equations for the preparation of the following ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Short Answer Question.
Identify the product (s) is/are formed when 1 – methoxy propane is heated with excess HI. Name the mechanism involved in the reaction.
Write the name of reagent and equation for the preparation of the following ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
