Advertisements
Advertisements
प्रश्न
Illustrate with examples the limitations of Williamson synthesis for the preparation of certain types of ethers.
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.
APPEARS IN
संबंधित प्रश्न
Write the reactions of Williamson synthesis of 2-ethoxy-3-methylpentane starting from ethanol and 3-methylpentan-2-ol.
Which of the following is an appropriate set of reactants for the preparation of 1-methoxy-4-nitrobenzene and why?
 |
 |
| (i) | (ii) |
Write the name of the reagent and the equation for the preparation of the following ether by Williamson’s synthesis:
Ethoxybenzene
Write the name of the reagent and the equation for the preparation of the following ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Write the name of the reagent and equation for the preparation of the following ethers by Williamson’s synthesis:
1-Methoxyethane
Account for the following :
t-butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butyl methyl ether.
Williamson's synthesis of preparing dimethyl ether is a/an ____________.
Which of the following cannot be made by using Williamson Synthesis:
Dehydration of alcohol to ethers is catalysed by:
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 ether 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
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 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 ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Write the name of reagent and equation for the preparation of the following ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Give the structure and IUPAC name of the metamers of 2-methoxy propane.
