(3R,4S)-1-Benzoyl-3-acetoxy-4-phenyl-2-azetidinone

(3R-cis)-3-(Acetyloxy)-1-benzoyl-4-phenyl-2-azetidinone was used to prepare synthesis of enantiomerically-pure 3-??hydroxy-??4-??phenyl β-??lactam derivatives I (R = 4-??MeOC6H4, H, Bz) via enzymic resolution.