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The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol . This reaction was developed by Alexander Williamson in 1850. [ 2 ] Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an S N 2 reaction .
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Alexander Williamson. Williamson is credited for his research on the formation of unsymmetrical ethers by the interaction of an alkoxide with a haloalkane, known as the Williamson ether synthesis. He regarded ethers and alcohols as substances analogous to and built up on the same type as water, and he further introduced the water-type as a ...
Usually phenol ethers are synthesized through the condensation of phenol and an organic alcohol; however, other known reactions regarding the synthesis of ethers can be applied to phenol ethers as well. Anisole (C 6 H 5 OCH 3) is the simplest phenol ether, and is a versatile precursor for perfumes and pharmaceuticals. [1]
Sodium phenoxide reacts with alkylating agents to afford alkyl phenyl ethers: [2] NaOC 6 H 5 + RBr → ROC 6 H 5 + NaBr. The conversion is an extension of the Williamson ether synthesis. With acylating agents, one obtains phenyl esters: [citation needed] NaOC 6 H 5 + RC(O)Cl → RCO 2 C 6 H 5 + NaCl
As a consequence, alkoxides (and hydroxide) are powerful bases and nucleophiles (e.g., for the Williamson ether synthesis) in this solvent. In particular, RO − or HO − in DMSO can be used to generate significant equilibrium concentrations of acetylide ions through the deprotonation of alkynes (see Favorskii reaction). [36] [37]
Figure 6:Reaction Coordinate Diagrams showing reactions with 0, 1 and 2 intermediates: The double-headed arrow shows the first, second and third step in each reaction coordinate diagram. In all three of these reactions the first step is the slow step because the activation energy from the reactants to the transition state is the highest.
The reaction is most successful when R is aliphatic and saturated, and typically performed with a silyl chloride reactant to trap the product as a disilyl enediol ether. The reaction is performed in aprotic solvents with a high boiling point, such as benzene and toluene, in an oxygen-free atmosphere (as even traces of oxygen interfere with the ...