Question

Acid-catalyzed dehydration of secondary and tertiary alcohols proceeds through an E1 mechanism. The first step is the protonation of alcohol and oxygen to form an oxonium ion.

Dehydration of 3-methyl-2-butanol forms one major and two minor organic products. Draw the structures, including hydrogen atoms, of the three organic products of this reaction.

The 3.) is correct that is the minor product I came up with but I cant get the answer correct for 1.) major product? and 2.) minor product

Answer 1

Concepts and reason

The concept of this problem is based on first order elimination reaction.

Elimination reactions involve the abstraction of proton in order to form alkene.

Elimination reactions are categorized in two categories which are E1 and E2 elimination reactions.

Fundamentals

E1 mechanism is a first order elimination reaction in which formation of a stable carbocation occurs in the presence of an acid followed by the removal of a proton to give a two or more alkene in which one is major and the other are minor products. The Zaitsev’s rule is followed according to which the more substituted alkene is formed as a major product.

The reaction is shown below:

The reaction takes place as follows:

Elimination of a proton gives the following products.

Abstraction of a proton from the adjacent carbon atom of the tertiary and secondary carbocation occurs by water to give two or more alkenes in which the more substituted alkene is major product according to Zaitsev’s rule.

Ans:

There are two minor and one major product.