Final answer:
There are six methods to synthesize alcohols from alkenes: acid-catalyzed hydration, hydroboration-oxidation, oxymercuration-demercuration, halohydrin formation, hydroxylation, and reduction of alkenes. The dehydration of alcohols is a reverse reaction that produces alkenes, not alcohols.
Step-by-step explanation:
To synthesize alcohols from alkenes, there are several methods available which include:
- Acid-catalyzed hydration: Adding water across the double bond in the presence of an acid such as H2SO4 or H3PO4.
- Hydroboration-oxidation: A borane (BH3) is added across the double bond, followed by oxidation to form an alcohol.
- Oxymercuration-demercuration: Mercuric acetate and water add across the double bond, followed by reduction to remove the mercury and form the alcohol.
- Halohydrin formation: Reaction with a halogen and water leads to a halohydrin, which can be converted to an alcohol.
- Hydroxylation: Using osmium tetroxide (OsO4) or potassium permanganate (KMnO4) to add two hydroxyl groups across the double bond, followed by splitting of the diol.
- Reduction of alkenes: Using hydrogen gas (H2) and a metal catalyst to add hydrogen atoms to the double bond and form an alcohol.
Note that the dehydration of alcohols is actually the reverse process, converting alcohols to alkenes, particularly at higher temperatures with excess acid. However, under different conditions, such as lower temperature and excess alcohol, dehydration can lead to ether formation, which is not the focus of this question.