The reactive nature of the oxygen in alcohol (-OH) proves this functional group useful for many different reactions and can be oxidized or used in nucleophilic substitutions; alcohol groups can also be protected via silyls.
Primary alcohols can be oxidized to form aldehydes and carboxylic acids.
Secondary alcohols can be oxidized to form ketones.
Tertiary alcohols cannot be oxidized.
Substitution reactions: SN1 or SN2
In nucleophilic substitution reactions, alcohols are considered the ideal leaving group.
In SN1 reactions, primary alcohols are favored.
In SN2 reactions, tertiary alcohols are favored.
2.Protection of alcohols
The easiest way to protect alcohol is with a silyl group (such as TMS or trimethylsilyl chloride), converting the alcohol from (-OH) to (-O-TMS). Alcohols protected with these can be protected using fluorine (F–).
- General reactivity of alcohols decreases as the number of substituents on an alcohol group increases; an exception is made for SN1 reactions
- Silyl groups can be used to protect alcohols, and fluorine can be used to deprotect.
- Primary alcohol: Alcohol with hydroxyl group connected to a primary carbon, also written as (-CH2OH)
- Secondary alcohol: Alcohol with hydroxyl group connected to secondary carbon, also written as (-CHROH)
- Tertiary alcohol: Alcohol with hydroxyl group connected to a tertiary carbon, also written as (-CHR2OH)
- “R” Group: Seen when defining the above carbons; used as an abbreviation for any group where carbon is attached to the rest of the molecule.