Draw the mechanism of the reaction of (E)-stilbene with Br2.
We can't draw diagrams on this forum. Sorry about that. I suggest you try Google. Many of the sites show the mechanism.
To draw the mechanism of the reaction between (E)-stilbene and Br2, we need to consider the addition of a bromine molecule across the double bond of (E)-stilbene. This reaction is commonly known as bromination.
Here is a step-by-step explanation of the mechanism:
Step 1: Initiation
The reaction begins with the initiation step, where the bromine (Br2) molecule is broken down into two bromine radicals. This can be achieved by exposing the Br2 to light or heat. The reaction is as follows:
Br2 -> 2 Br•
Step 2: Propagation
In the second step, one of the bromine radicals (Br•) attacks the double bond of (E)-stilbene. This creates a resonance-stabilized intermediate, known as a bromonium ion. The reaction proceeds as follows:
(E)-stilbene + Br• -> (E)-stilbene Br•
Step 3: Rearrangement
The bromonium ion undergoes a rearrangement, specifically a ring-opening step. This occurs as one of the carbons bonded to the bromine is attacked by a bromide ion. The result is a more stable carbocation intermediate. The reaction is as follows:
(E)-stilbene Br• + Br¯ -> Br-(E)-stilbene-Br
Step 4: Termination
Finally, the bromide ion (Br¯) reacts with the remaining bromonium ion, resulting in the formation of the final product, which is trans-1,2-dibromostilbene. The reaction is as follows:
Br-(E)-stilbene-Br + Br¯ -> trans-1,2-dibromostilbene
This completes the mechanism of the reaction between (E)-stilbene and Br2, resulting in the formation of trans-1,2-dibromostilbene.