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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:
Write the equations involved in the following reactions : Williamson synthesis
Write the name of the reagent and the equation for the preparation of the following ether by Williamson’s synthesis:
Ethoxybenzene
Explain the following with an example.
Williamson ether synthesis
Which of the following cannot be made by using Williamson Synthesis:
Which of the following reactions are feasible?
Write the mechanism of the following reaction:
\[\ce{2CH3CH2OH ->[H^+][413 K] CH3-CH2-O-CH2-CH3 + H2O}\]
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 reagent and equation for the preparation of the following ethers by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Write the name of the reagent and equation for the preparation of the following ether 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
Identify the product(s) is/are formed when 1-methoxy propane is heated with excess HI. Name the mechanism involved in the reaction.
Predict the major product, when 2-methyl but -2-ene is converted into an alcohol in the following method.
Acid catalysed hydration
Write the names of reagents and equations for the preparation of the following ether 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
Give the structure and IUPAC name of the metamers of 2-methoxy propane.
