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The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and an alcohol. This reaction was developed by Alexander Williamson in 1850.〔 ((Link to excerpt. ))〕 Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an SN2 reaction. This reaction is important in the history of organic chemistry because it helped prove the structure of ethers. The general reaction mechanism is as follows: An example is the reaction of sodium ethoxide with chloroethane to form diethyl ether and sodium chloride: :Na+C2H5O− + C2H5Cl (unicode:→) C2H5OC2H5 + Na+Cl− ==Scope== The Williamson reaction is of broad scope, is widely used in both laboratory and industrial synthesis, and remains the simplest and most popular method of preparing ethers. Both symmetrical and asymmetrical ethers are easily prepared. The intramolecular reaction of halohydrins in particular, gives epoxides. In the case of asymmetrical ethers there are two possibilities for the choice of reactants, and one is usually preferable either on the basis of availability or reactivity. The Williamson reaction is also frequently used to prepare an ether indirectly from two alcohols. One of the alcohols is first converted to a leaving group (usually tosylate), then the two are reacted together. The alkoxide (or aroxide) may be primary, secondary or tertiary. The alkylating agent, on the other hand is most preferably primary. Secondary alkylating agents also react, but tertiary ones are usually too prone to side reactions to be of practical use. The leaving group is most often a halide or a sulfonate ester synthesized for the purpose of the reaction. Since the conditions of the reaction are rather forcing, protecting groups are often used to pacify other parts of the reacting molecules (e.g. other alcohols, amines, etc.) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Williamson ether synthesis」の詳細全文を読む スポンサード リンク
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