A Lewis Base–Silyl Lewis Acid Cooperative Catalyst for the Iodochlorination of Tetrasubstituted Alkenes

We have developed a Lewis base–silyl Lewis acid cooperative catalyst for the iodochlorination of alkenes. In the presence of 10–20 mol% of Ph3P=O, the iodochlorination of tetrasubstituted alkenes with N-iodosuccinimide and tert-butyldimethylchlorosilane proceeded efficiently at –40 °C to provide the corresponding 1,2-iodochloroalkanes that cannot be easily obtained via conventional methods. A series of 31P NMR experiments suggests that the cooperative activation of the reaction components facilitates the generation of the active iodochlorinating species.