α @-@ Hydroxyketones , or acyloins , are an important synthetic motifs present in many natural products. α @-@ Hydroxyketones have been synthesized in many ways , including reduction of α @-@ diketones , substitution of a hydroxyl for a leaving group and direct oxidation of an enolate . Oxodiperoxymolybdenum ( pyridine ) - ( hexamethylphosphoric triamide ) ( MoOPH ) and N @-@ sulfonyloxaziridines are the most common electrophilic sources of oxygen implemented in this process . One advantage of using N @-@ sulfonyloxaziridines is that higher chiral induction is almost invariably observed relative to MoOPH and other oxidants . High yield ( 77 @-@ 91 % ) and dr ( 95 : 5 - 99 : 1 ) are reported for α @-@ hydroxylation with the Evans ' chiral auxiliary with N @-@ sulfonyloxaziridine as the electrophile . Chiral induction has been demonstrated with many other chiral ketones and ketones with chiral auxiliaries , including SAMP and RAMP .