Substitution reaction in alcohols.

The mechanism of substitution of alcohols is similar to the reactions of substitution of alkyl halides. There are two ways to do this:

1) Use an acid to protonate OH. Reagents HCl, HBr and HI are usually used in substitution reactions. The mechanism will be SN2 or SN1 depending on whether the alcohol is primary, secondary, or tertiary methyl. Methyl and primary alcohols react via SN2, while secondary and tertiary alcohols react via SN1. Attached alcohol 3 gives information about mechanisms and speeds. Alcohol Attached 2
shows the reaction mechanism.

2) Use mesyl chloride or tosyl chloride to convert alcohol to mesylate or tosylate. These groups are very good leaving groups and are easily moved by a number of nucleophiles.