Condition
- Strong nucleophile
Alcohols will dehydrate in acidic, hot conditions. When treated with a strong nucleophile, alcohols will instead react by either SN1 or SN2
SN2 –substitution nucleophilic bimolecular
Possible with both primary and secondary alcohol NOT tertiary due to steric hinderance.
Steric hinderance – the tertiary site is much too bulky to allow an SN2 mechanism.
All three examples below follow SN2. Notice that the alcohols are each converted into a better leaving group before the substitution occurs
With PBr3 (note that one molecule of PBr3 can donate 3 bromines)
With SOCl2
With sulfonate esters
Below is an example of SN1 using a generic alkyl halide
With HX
