Show how would you synthesise the following alcohols from appropriate alkenes?
Show how would you synthesise the following alcohols from appropriate alkenes?
Solution and Explanation
The given alcohols can be synthesized by applying Markovnikov's rule of acid-catalyzed hydration of appropriate alkenes.
(iii)Acid-catalyzed hydration of pent-2-ene also produces pentan-2-ol but along with pentan-3-ol.Thus, the first reaction is preferred over the second one to get pentan-2-ol.
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Notes on Alcohols, Phenols And Ethers
Concepts Used:
Preparation - Alcohols, Phenols and Ethers
Alcohols, phenols, and ethers are organic compounds that can be prepared by various methods.
Preparation of Alcohols:
- Direct hydration of alkenes: Alcohols can be prepared by the addition of water to an alkene in the presence of a strong acid catalyst.
- Reduction of carbonyl compounds: Alcohols can be prepared by the reduction of aldehydes, ketones, or carboxylic acids using reducing agents like NaBH4 or LiAlH4.
- Grignard reaction: Alcohols can be prepared by reacting Grignard reagents with carbonyl compounds.
- Hydroboration-oxidation: Alcohols can be prepared by the hydroboration of alkenes followed by oxidation with an oxidizing agent like H2O2.
Preparation of Phenols:
- Hydrolysis of diazonium salts: Phenols can be prepared by the hydrolysis of diazonium salts, which are formed by the reaction of aniline with nitrous acid.
- Oxidation of sulfonic acids: Phenols can be prepared by the oxidation of sulfonic acids using strong oxidizing agents like potassium permanganate or chromic acid.
Preparation of Ethers:
- Williamson synthesis: Ethers can be prepared by the reaction of an alkoxide ion with a primary alkyl halide or tosylate in the presence of a strong base like NaOH or KOH.
- Dehydration of alcohols: Ethers can be prepared by the dehydration of alcohols in the presence of a strong acid catalyst like H2SO4.
In summary, alcohols, phenols, and ethers can be prepared by a variety of methods, including hydration, reduction, Grignard reaction, hydroboration-oxidation, hydrolysis, oxidation, Williamson synthesis, and dehydration. The choice of the method depends on the availability of starting materials, the desired product, and the conditions of the reaction.