CHEM 102 Lecture Notes - Lecture 6: Deprotonation, Ion, Organochloride
Document Summary
The leaving group changes and the reaction conditions are very different but the overall process is elimination of hx to produce one of two alkenes. In the first example acid-catalysed elimination of water from a tertiary alcohol produces a trisubstitued alkene. Elimination of hcl from the corresponding tertiary alkyl chloride promoted by a very hindered alkoxide base (more hindered than t-buok because all the ethyl groups have to point away from one another) gives exclusively the less stable disubstituted alkene. The reason for the two different regioselectivities is a change in mechanism. As we have already discussed, acid-catalysed elimination of water from tertiary alcohols is usually e1, and you already know the reason why the more substituted alkene forms faster in e1 reactions (p. 000). It should come to you as no surprise now that the second elimination, with a strong, hindered base, is an e2 reaction.
