Question

Which isomer was produced from the bromination of trans-stilbene and cis-stilbene? Draw the structures of the products (use solid and dashed wedges).

Answer 1

See picture

Step-by-step explanation:

To do this, we know that we have cis and trans stilbene. Two reactants apart. Now, we do the bromination reaction with both reactants and see what happens.

In the case of the cis, the bromination will occur for the side of the hydrogens, because the phenyls cause steric hindrance. Then, the other bromine, will go to the same side because of the steric hindrance of the phenyl. The final product would be the 1S, "s or 1R, 2R (Depending on the side which the bromine enters).

In the case of the trans, the bromination can occur in either side because there are no steric hindrance. When the 2nd bromine enters, it will also do it in the two sides of the molecule, either one of them. The final product would be the meso configuration.

See picture below