The direct asymmetric organocatalytic α-oxidation of aldehydes using trans-2-(p- methylphenylsulfonyl)-3-phenyloxaziridine is reported. This method affords the S isomer of α- hydroxy aldehydes, thereby complementing the selectivity for the R isomer observed using the two-step nitrosobenzene method. Use of α-methylproline and α-methylproline tetrazole significantly increases the enantioselectivity observed for the α-oxidation of aldehydes ...