Catalyst-free, High-yield, and Stereospecific Synthesis of 3-Phenylthio β-Lactam Derivatives

α-Diazocarbonyl compounds are good precursors of ketenes in the Staudinger reaction. On the basis of the reactions of S-phenyl diazothioacetate with imines under the catalysis of Rh2(OAc)4 a method for the synthesis of 3-phenylthio β-lactam derivatives has been developed previously. In this paper, a more convenient and improved procedure was achieved, which simplified the synthesis of S-phenyl diazothioacetate and made the reaction work well without the expensive Rh2(OAc)4 catalyst. The catalyst-free reactions of S-phenyl diazothioacetate with a variety of imines produced monocyclic and polycyclic β-lactams stereospecifically in good to excellent yields.