Lactones, cyclic esters such as compound A, are prepared by halolactonization, an addition...

Lactones, cyclic esters such as compound A, are prepared by halolactonization, an addition reaction to an alkene. For example, iodolactonization of B forms lactone C, a key intermediate in the synthesis of prostaglandin PGF2α (Section 4.15). Draw a stepwise mechanism for this addition reaction.