Diastereoselective addition of Grignard reagents to α-epoxy N-sulfonyl hydrazones

α-Substituted-β-hydroxy ketones are valuable intermediates, but their preparation by alkylation of enolates is difficult with hindered electrophiles. Now, a direct method for preparing α-substituted-β-hydroxy ketones — including those having α-quaternary centres — by addition of Grignard reagents to epoxyhydrazones has been developed, enabling the stereocontrolled incorporation of a wide range of carbon based substituents.