Etherification via Aromatic Substitution on 1,3-Disubstituted Benzene Derivatives

Area of Science:

• Organic Chemistry
• Synthetic Methodology

Background:

• Aromatic substitution reactions are fundamental in organic synthesis.
• Activating aromatic substrates with electron-withdrawing groups (EWGs) is crucial for nucleophilic aromatic substitution.
• Developing efficient methods for etherification, especially with challenging substrates, remains an active area of research.

Purpose of the Study:

• To develop a new method for etherification via aromatic substitution.
• To achieve substitution at the ipso-position of an electron-withdrawing group (EWG) meta to another EWG.
• To enable the synthesis of ethers from previously unreactive aromatic substrates.

Main Methods:

• Utilized a potassium tert-butoxide (t-BuOK) solution in tetrahydrofuran (THF).
• Employed 18-crown-6-ether as an additive in dimethylformamide (DMF).
• Investigated the reaction sequence involving aromatic substrates and alcoholic nucleophiles.

Main Results:

• Successfully achieved etherification via aromatic substitution at the ipso-position of a meta-disubstituted EWG system.
• Demonstrated the effective conversion of challenging substrates, including aryl fluorides activated by bromide or chloride substituents.
• The reaction proceeded efficiently at 25 °C, indicating mild reaction conditions.

Conclusions:

• The developed method provides an effective route for synthesizing aryl ethers.
• This methodology broadens the scope of nucleophilic aromatic substitution, particularly for activated aryl fluorides.
• The residual halide substituent offers potential for further chemical transformations, enabling diverse molecular constructions.