Question

Draw the major E2 reaction product formed when cis-1-chloro-2-ethylcohexane (shown below) results with hydroxide ion in DMSO.

Draw the major E2 reaction product formed when cis-1-chloro-2-ethylcyclohexane (shown below) reacts with hydroxide ion in DMSO.

Answer 1

Concepts and reason

An E2 elimination reaction is a bi-molecular elimination reaction. This elimination process is single-step process which follows a concerted mechanism. In an E2 elimination reaction, the intermediate is in transition state. The rate of the reaction depends on both the base and the substrate; therefore, an E2 elimination reaction is known as a bi-molecular elimination reaction.

Fundamentals

In an E2 elimination reaction, the alkene product is based on the base used in the reaction to attract the acidic proton in the substrate. If a bulky base that is steric crowded is used, a Hoffman alkene is the product; if the base is not steric hindered, then a highly substituted alkene is the product according to Zaitsev’s rule.

The given substrate is cis-1-chloro-2-ethylcyclohexane

The structure of the substrate is shown below.

The ring flip of the given substrate is shown below.

Given base is ${\rm{O}}{{\rm{H}}^{\rm{ - }}}$

The base attack on the given substrate cis-1-chloro-2-ethylcyclohexane is shown below.

The eliminated product of the given substrate is shown below.

Ans:

The complete reaction