HF/AsF5 and HF/SbF5 superacid mixtures react with fluorinated small-ring heterocycles such as 1, 2-oxazetidines and oxetanes with consequent addition of HF to give alcohol and amine ring-opened products in high yield. Excess HF serves as solvent and reactant. Ring compounds containing both nitrogen and oxygen as heteroatoms protonate predominantly on nitrogen; a case with competing O-protonation arises in the case of a chloro-substituted ...
