Alcohols are important intermediates in organic synthesis, as they can undergo various reactions to form different functional groups. One of the common ways to prepare alcohols is by using alcohols as reagents for chemical synthesis.

There are several methods to use alcohols as reagents for chemical synthesis, depending on the type of alcohol and the desired product. Some of these methods are:

• Oxidation: Alcohols can be oxidized to ketones, aldehydes or carboxylic acids by using oxidizing agents such as chromic acid, pyridinium chlorochromate or biological enzymes. The oxidation level depends on the degree of substitution of the alcohol and the strength of the oxidant.
• Dehydration: Alcohols can be dehydrated to form alkenes by using acid catalysts such as sulfuric acid or phosphoric acid. The dehydration follows Zaitsev's rule, which states that the major product is the more substituted alkene.
• Substitution: Alcohols can be converted to alkyl halides by using halogen acids such as hydrochloric acid, hydrobromic acid or hydroiodic acid. The substitution follows SN1 or SN2 mechanism, depending on the degree of substitution of the alcohol and the nucleophilicity of the halide ion.
• Esterification: Alcohols can react with carboxylic acids or acid derivatives to form esters by using acid catalysts such as sulfuric acid or p-toluenesulfonic acid. The esterification is a reversible reaction, which means that excess alcohol or carboxylic acid is needed to drive the equilibrium to completion.
• Reactions of alkoxides: Alkoxides are negatively charged oxygen atoms bonded to alkyl groups, which are formed by reacting alcohols with strong bases such as sodium hydride or potassium hydroxide. Alkoxides are strong nucleophiles and bases that can react with electrophiles such as alkyl halides, epoxides or carbonyl compounds.

These are some examples of how alcohols can be used as reagents for chemical synthesis. By choosing appropriate alcohols and reaction conditions, a variety of organic compounds can be synthesized from alcohols.