During the acid-catalyzed dehydration of 3,3-dimethyl-2-butanol, the initial intermediate is a secon — Reaction Mechanism Chemistry Question
Question
During the acid-catalyzed dehydration of 3,3-dimethyl-2-butanol, the initial intermediate is a secondary carbocation. What specific type of rearrangement occurs to yield the major alkene product?
💡 Solution & Explanation
Protonation and loss of water from 3,3-dimethyl-2-butanol yields the 3,3-dimethyl-2-butyl secondary carbocation. The adjacent carbon is a quaternary center with three methyl groups. A 1,2-methyl shift occurs, moving a methyl group with its bonding electrons to the secondary carbon, thereby creating a significantly more stable tertiary carbocation (2,3-dimethyl-2-butyl cation), which then loses a proton to form tetramethylethylene (2,3-dimethyl-2-butene).