Assuming one uses 1-equivalent of t-butyl alcohol, why is it difficult to stop the reaction at the mono-alkylated product (1-t-butyl-2,5-dimethoxy benzene)?
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.
Assuming one uses 1-equivalent of t-butyl alcohol, why is it difficult to stop the reaction at the mono-alkylated product (1-t-butyl-2,5-dimethoxy benzene)?
Since methoxy group is an activating group hence substitution occurs at Ortho position to methoxy group.
Since both methoxy group and tertiary butyl group up in the mono alkylated product are electron donating groups hence benzene ring is more electron rich so further substitution occurs at Ortho position to methoxy group.
Whereas in ethyl benzoic acid, carboxylic acid group is is electron withdrawing group hence it decreases the electron density in the benzene ring hence second alkylation is not possible.
Alkylation at meta position to carboxylic acid group.
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