As shown below, when cis-2-butene reacts with dichlorocarbene, only the cis-1,1-dichloro-2,3-dimethylcyclopropane is formed. What can we conclude about the nature of the reaction mechanism?

Question

Quizplus · Accepted Answer

The fact that only one product is formed and that it is the cis isomer suggests that the reaction is not proceeding through a radical intermediate. Additionally, the formation of a cyclopropane ring suggests that it is not an E2 mechanism. The only remaining option is a concerted mechanism, in which the reaction occurs in a single step with no intermediates. Therefore, the best choice is B.

As Shown Below, When Cis-2-Butene Reacts with Dichlorocarbene, Only the Cis-1,1-Dichloro-2,3-Dimethylcyclopropane