1,5-cyclooctadiene is treated with I-Cl. What is the structure of product?
If I-Cl is in excess:
1,5-dichloro-2,6-diiodocyclooctane + 1,6-dichloro-2,5-diiodocyclooctane. There is no regioselectivity, so the reaction by chloride can occur with the intermediate at either position, creating mixtures of diastereomers and other isomers.
Unlike an iodolactonization, the electrophilic iodine will cleave the pi-bond to create a three centered bridge-like complex (not cyclic iodinium, which doesn't form). Chloride will attack to give predominantly trans (vic) chloro, iodo oxidation at the former alkene bonds--at one or at both depending on concentration and the use of excess reagent.