Question

Draw the Zaitsev product formed when 2,3-dimethylpentan-3-ol undergoes an E1 dehydration.

Draw the Zaitsev product formed when 2,3-dimethylpentan-3-ol undergoes an E1 dehydration.

Answer 1

Concepts and reason

The concept of dehydration reaction of 2, 3-dimethylpentan-3-ol in acidic medium is used in the problem. The dehydration id taking place through ${{\rm{E}}_{\rm{1}}}$ mechanism and the product is formed through Zaitsev rule.

Fundamentals

Dehydration means removal of ${{\rm{H}}_{\rm{2}}}{\rm{O}}$ molecule. First the nucleophile ${\rm{O}}{{\rm{H}}^{\rm{ - }}}$ is removed followed by ${{\rm{H}}^ + }$ leaving behind a double bond. It is an elimination reaction.

It takes place through ${{\rm{E}}_{\rm{1}}}$ mechanism which includes the carbocation mechanism and the product is formed through Zaitsev rule which states that more alkylated alkene is more stable.

The possible products of dehydration of 2, 3-dimethylpentan-3-ol are shown as follows

The most stable product (Zaitsev product) of dehydration of 2, 3-dimethylpentan-3-ol is shown as follows

Ans:

The Zaitsev product formed when 2, 3-dimethylpentan-3-ol undergoes an ${{\rm{E}}_{\rm{1}}}$ dehydration is,