Organo Sulfonic Peracids. 4.¹ The Reaction of Arenesulfonylimidazoles with H₂O₂ in the Presence of Ketones. A New Entry to Dioxiranes

Abstract

The reaction of ketones (acetone, 1,1,1-trifluoropropan-2-one) with the oxidation system (arenesulfonyl)imidazole (2)/H(2)O(2)/NaOH permits the in situ generation of the corresponding dimethyl- and methyl(trifluoromethyl)dioxirane in various solvents. This has been established by the chemoselective oxidation of azomethines 6, the diastereoselective oxidation of cholesterol (12), and (18)O-labeling experiments. Because only 5 equiv of ketone are used, the dioxirane oxidation pathway appears to be virtually exclusive one in this system. One example for the nonaqueous in situ generation of dimethyldioxirane (1a) is given.