Which is the major product from acid catalyzed hydration (addition of water) of 2-methyl-2-pentene?
a) 2-methyl-2-pentanol
b) 2-methyl-1-pentanol
c) 2-methyl-3-pentanol
d) 3-methyl-3-pentanol
answer: "c": 2-methyl-3-pentanol ???
I'm not an organic chemist but from what I can read I think the answer is a.
I think that it must be "a", too, when I rethought it. Thank you.
"A" was correct
To determine the major product from the acid-catalyzed hydration of 2-methyl-2-pentene, we need to understand the mechanism involved.
In acid-catalyzed hydration, water adds to an alkene to form an alcohol. The addition of water involves the formation of a carbocation intermediate. The carbon atom that carries the positive charge determines the structure of the final alcohol product.
For the given compound, 2-methyl-2-pentene, the carbon atom adjacent to the double bond (the beta-carbon) is a tertiary carbon. In acid-catalyzed hydration, tertiary carbocations are more stable than secondary or primary carbocations. Therefore, the major product is expected to have the carbocation formed on the most substituted carbon.
In the case of 2-methyl-2-pentene, the double bond is located between the second and third carbons. When water adds to the double bond, a tertiary carbocation is formed on the third carbon. This results in the following product:
c) 2-methyl-3-pentanol
So, according to the mechanism and stability of the carbocation intermediate, the major product of acid-catalyzed hydration of 2-methyl-2-pentene is indeed 2-methyl-3-pentanol (option c).