here for the first time are the developments of an efficient method for oxidativecleavage of carbon−carbon double bonds yielding carbonyl compounds by using aryl-λ3-iodanes, which involve a combination of iodosylbenzene and HBF4 in the presence of water. The method serves as a safety alternative to ozonolysis. The oxidativecleavage of olefins probably involves the hitherto unknown direct vicinal dihydroxylations