Question

Identify the one alkene that will not rearrange in the course of an electrophilic addition.

• A. $vinylcyclopropane$
• B. $2$$-methyl-$$2$$-butene$
• C. $methylenecyclopropene$
• D. $3,3$$-dimethyl$$1$-$1$$-butene$

Answer 1

Answer: (B)

$2$$-methyl-$$2$$-butene$

A carbocation from an unstable state to a more stable state through the use of various structural reorganizational "shifts" within the molecule. Once the carbocation has shifted over to a different carbon, is called rearrangement.

$2-methyl-2-butene$ forms a secondary carbocation which is already stable therefore do not undergo rearrangement.