These posts contain the computed potential energy surfaces for a fair few “text-book” reactions. Here I chart the course of the cyclopropanation of alkenes using the Simmons-Smith reagent,[cite]10.1021/ja01552a080[/cite] as prepared from di-iodomethane using zinc metal insertion into a C-I bond. Two reactions it can be compared with are the epoxidation of ethene using a peracid and dichlorocyclopropanation.