Visible-light-triggered Catalytic Halohydrin Synthesis from Epoxides and Trichloroacetonitrile by Copper and Iron Salts

Preparation of vicinal halohydrins, in which copper or iron chlorides catalyze the ring-opening reaction of epoxides with visible light effectively, is described. The use of trichloroacetonitrile as a halogen source enables catalytic HCl generation under the mild conditions. This method can also be applied to the aziridine ring-opening reaction. Preparation of vicinal halohydrins, in which inexpensive metal chlorides catalyze the ring-opening reaction of epoxides with visible light effectively, is described. The use of trichloroacetonitrile as a halogen source enables catalytic HCl generation under the mild conditions. In addition, N-tosylaziridines are applicable to give not only the HCl adducts but also the MeOH adducts.