Search results
Results from the WOW.Com Content Network
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 .
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 ...
In figure 11 below the rate determining step for Williamson ether synthesis is shown. [9] [10] The starting material is methyl chloride and an ethoxide ion which has a localized negative charge meaning it is more stable in polar solvents. The figure shows a transition state structure as the methyl chloride undergoes nucleophilic attack.
Williamson ether synthesis; R−Br + OR' − → R−OR' + Br − (S N 2) The Wenker synthesis, a ring-closing reaction of aminoalcohols. The Finkelstein reaction, a halide exchange reaction. Phosphorus nucleophiles appear in the Perkow reaction and the Michaelis–Arbuzov reaction. The Kolbe nitrile synthesis, the reaction of alkyl halides ...
In the IUPAC Nomenclature system, ethers are named using the general formula "alkoxyalkane", for example CH 3 –CH 2 –O–CH 3 is methoxyethane. If the ether is part of a more-complex molecule, it is described as an alkoxy substituent, so –OCH 3 would be considered a "methoxy-" group.
For example, the synthesis of macrocidin A, a fungal metabolite, involves an intramolecular ring closing step via an S N 2 reaction with a phenoxide group as the nucleophile and a halide as the leaving group, forming an ether. [2] Reactions such as this, with an alkoxide as the nucleophile, are known as the Williamson ether synthesis.
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]
This reaction is the reverse of the formation reaction from an epoxide and can be considered a variant of the Williamson ether synthesis. Most of the world's supply of propylene oxide arises via this route. [7] Such reactions can form the basis of more complicated processes, for example epoxide formation is one of the key steps in the Darzens ...