Answers to the Exercises "SN/E Competition"
With tetrabutylammonium chloride in acetone mainly (about 96 %) E1 elimination occurs. Due to the stabilization by three alkyl substituents, the tert-butyl carbenium ion is easily formed. Consequently, the reaction displays a unimolecular mechanism with an intermediate carbenium ion. Chloride anions, as well as acetone molecules, are poor nucleophiles and rather weak bases. Therefore, neither a reaction by a nucleophilic attack on the carbenium ion, nor an E2 elimination through the abstraction of the β proton by a strong base in the early phase of the reaction can take place.