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
How do you convert the following :
Phenol to anisole
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:
1-Propoxypropane
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 equation for the preparation of the following ethers by Williamson’s synthesis:
1-Methoxyethane
Preparation of ethers by acid dehydration of secondary or tertiary alcohols is not a suitable method. Give reason.
Write the structure of 3-Bromo-2-methylprop-1-ene
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 ____________.
HBr reacts with \[\ce{CH2 = CH - OCH3}\] under anhydrous conditions at room temperature to give ______.
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
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
Predict the major product, when 2-methyl but -2-ene is converted into an alcohol in the following method.
Acid catalysed hydration
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
Write the name of reagent and equation for the preparation of the following ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
