An unprecedented asymmetric alpha-sulfenylation of 5H-oxazol-4-ones to N-(sulfanyl)succinimides has been established, to access various alpha-sulfenylated adducts with good to excellent enantioselectivities (86-95% ee) by utilizing a cinchona alkaloid-derived squaramide as catalyst. The conditions of this alpha-sulfenylation protocol simultaneously satisfy N-(arylthio)succinimides, N-(benzylthio)succinimides, and N-(alkylthio)succinimides by tuning the substituted groups of 5H-oxazol-4-ones on the 2-position as well as additives. (C) 2014 Elsevier Ltd. All rights reserved.