In the second step in olefin metathesis the ____.
A)metal alkylidene ([M]=)undergoes a [2+2] pericyclic addition with an alkene alkene to form a metalcyclobutane intermediate
B)metalcyclobutane undergoes a reverse [2+2] addition (i.e.,retro [2+2] reaction)to generate a new metal alkylidene
C)reaction of the new metal alkylidene with a new alkene (by [2+2] addition)to generate a new metalcyclobutane intermediate
D)formation of the alkene product from a retro [2+2] reaction of the second metal alkylidene
E)alkene reacts with a second alkene by [2+2] addition

Question

Quizplus · Accepted Answer

In the second step of olefin metathesis, the metalcyclobutane intermediate formed in the first step undergoes a reverse [2+2] addition (retro [2+2] reaction) to regenerate a new metal alkylidene. This step is commonly referred to as the dissociation or cleavage step. Option A describes the first step in olefin metathesis, option C describes the third step, option D describes a hypothetical step that does not occur, and option E describes a reaction that may occur in other contexts but not in the second step of olefin metathesis.

In the Second Step in Olefin Metathesis the ____