91Ó°ÊÓ

3-methyl-1-butyne undergoes reaction with H₂in presence of Lindlar catalyst and H₂O and H₂SO₄to form 2-methyl-2-butanol.

Because water will occasionally attack the secondary carbocation before it has a chance to rearrange to the tertiary carbocation, 3-methyl-2-butanol will be formed from 1.

Because boron can also add to the other sp² carbon in the second stage of synthesis, 3-methyl-2-butanol will be the minor product, and the transition state for its creation is less stable than the transition state leading to the major product. A carbocation rearrangement is not possible since the carbocation is not produced as an intermediate.

(The proton cannot join to the other sp² carbon in part 1 since this would necessitate the production of a primary carbocation in the second stage of the synthesis, which is extremely unstable.)