| abstract |
A process for preparing (1'R,3S)-3-(1'-hydroxyethyl)-azetidin-2-one or a derivative thereof represented by formula (I): ##STR1## wherein R 1 represents a hydrogen atom or a hydroxyl-protective group, is disclosed, comprising reacting (2S,3R)-2-aminomethyl-3-hydroxybutyric acid or a derivative thereof represented by formula (II): ##STR2## wherein R 1 is as defined above, with a sulfenamide represented by formula (III): ##STR3## wherein R 2 represents ##STR4## and R 3 and R 4 each represent a hydrogen atom or a cyclic or acyclic hydrocarbon group, provided that they do not simultaneously represent a hydrogen atom, or R 3 and R 4 are taken together with the adjacent nitrogen atom to form a heterocyclic group, and triphenylphosphine. The reaction yield is high, and the sulfenamide (III) used as a lactamization reagent is cheap and can be recovered after the reaction. |