Organic Chem - Kaplan diagnostic

[412smb412]

Advertisement - Members don't see this ad

1. Which is more stable?

cycloalkene or 2,4-dimethylbut-2-ene

i always thought that rings with an alkene are more stable...



2. which is the slowest for sn2?

tertiary carbocation or secondary with resonance?

i chose the secondary with resonance b/c sn2 doesn't occur with tertiary carbocations...?

 

[412smb412]

Any1??

 

[MotivatedToWin]

The first one is tricky. Cyclohexane/ene rings have the most stable ring strain compared to other rings. But in this case the 2,4-methylbut-2-ene is more stable because of the substituents on the carbons. They are tertiary carbons instead of secondary.

Sn2 reactions are slowest in tertiary carbons. I'm taking the DAT friday and I realized with questions like this, they ask basically which one is NOT going to happen. The secondary with resonance can still happen because it is much more stable.

 

[412smb412]

The first one is tricky. Cyclohexane/ene rings have the most stable ring strain compared to other rings. But in this case the 2,4-methylbut-2-ene is more stable because of the substituents on the carbons. They are tertiary carbons instead of secondary.

Sn2 reactions are slowest in tertiary carbons. I'm taking the DAT friday and I realized with questions like this, they ask basically which one is NOT going to happen. The secondary with resonance can still happen because it is much more stable.

thanks