[rleung]

Hey,

I have a question about the reaction of sulfuric acid with 4-methyl-2-pentanol.  Would there only be two products, the first and major product being 4-methyl-2-pentene and the second, minor product being 4-methyl-1-pentene?  Thanks.

Ryan

[movies]

One of them will be highly favored because these types of dehydrations are under thermodynamic control.

By the way, this is an E1 elimination.  Rearrangements are different.

[FeLiXe]

Wagner-Meerwein rearrangement only works if you have a methyl group right next to the carbenium ion. And the resulting ion should be more stable. 3,3-Dimethyl-pentan-2-ol could rearrange if you dehydrate it.

[rleung]

But the possibilities I listed should be the only ones, right?  As in, did I miss any?  Thanks.

[movies]

Structurally, yes.  There is the possibility of cis/trans stereoisomers with one of them though.

[rleung]

Hmm, actually, my teacher is now saying that the dehydration of 4-methyl-2-pentanol gives a mixture of 5 isomeric alkenes, but I only count 3 (4-methyl-1-pentene, (E)-4-methyl-2-pentene, and (Z)-4-methyl-1-pentene).  Am I missing something?  Thanks.

Ryan

[movies]

Ah, I see.  I think once you figure out the answer to your question in the other thread, you will see the answer to this one as well.