Chlorine addition to E-2-butene

Next we take again E-2-butene, and let a second chlorine attack the chloronium ion. Replacing the OH by chlorine gives the following four structures:

A B
C D

Question 9: Again, how are these four compounds related?

  1. A and B identical, C and D identical; A/B and C/D different compounds
  2. A and C identical, B and D identical; A/C and B/D different compounds
  3. A and B identical, C and D identical; A/B and C/D mirror images
  4. A and C identical, B and D identical; A/C and B/D mirror images
  5. All compounds are identical

The correct answer should support our remark, that the erythro stereo pair on the previous page corresponds to a meso compound if the chiral centers carry the same substituents.

Can you now predict which compound(s) the reaction of chlorine with Z-2-butene would yield?

We conclude with a quiz!


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