Question

2. Draw the products you get with syn- and anti-addition of bromine to Z-stilbene. For each of these additions, do you get the meso compound or the racemic mixture? (You did the E-stilbene equivalent in your Prelab.)

Answer 1

The General concept is

Symmetric Cis alkenes:

Syn addition gives Meso Compound.

Anti addition results in two enantiomers- Racemic Mixture.

SymmetricTrans alkenes:

Anti addition gives Meso compound.

Syn addition gives of enantiomers- Racemic Mixture.

Now we are taking cis alkene which Z stilbene and performing Syn addition Meso compound Br Br Syn Addition of Br (1R,2S)-1,2-dibromo-1,2-diphenylethane Now we are taking cis alkene which Z stilbene and performing anti addition Racemic mixtures Br Br Br Br Syn Addition of Br (1R,2R)-1,2-dibromo-1,2-diphenylethane (1S,2S)-1,2-dibromo-1,2-diphenylethane