A straightforward and highly diastereoselective synthesis of beta-(aziridin-2-yl)-beta-hydroxy ketones was achieved by the Mukaiyama aldol reaction of optically pure 1-(alpha-methylbenzyl)-aziridine-2-carboxaldehyde and various enol-silanes in ZnCl2 via a chelation-controlled transition state (98 : 2 dr and >82% yields). These beta-(aziridin-2-yl)-beta-hydroxy ketones were applied for the synthesis of various alkaloids including epiallo-isomuscarine, epi-enigmol, and epi-galantinic acid.