When vinylic boronic acids are treated with Br2 and then with NaOH, vinylic bromides are
Chapter 18, Problem 18.89(choose chapter or problem)
When vinylic boronic acids are treated with Br2 and then with NaOH, vinylic bromides are formed with inversion of configuration, as shown in Fig. P18.89a on p.944. But when vinylic boronic acids are treated with I2 in the presence of NaOH, vinylic iodides are formed with retention of configuration, as shown in Fig. P18.89b. Suggest mechanisms that account for these results. (Hint: Iodine does not add to double bonds, but it does form iodohydrins (Sec. 5.2B). Remember the stereochemistry of halogen addition.)
Unfortunately, we don't have that question answered yet. But you can get it answered in just 5 hours by Logging in or Becoming a subscriber.
Becoming a subscriber
Or look for another answer