S-[(2R,3S)-3-[(1R)-1-[tert-butyl(dimethyl)silyl]oxyethyl]-4-oxoazetidin-2-yl] 2-[tert-butyl(diphenyl)silyl]oxyethanethioate 、 pivaloyloxymethyl glyoxalate 生成 2,2-Dimethyl-propionic acid 2-{(2R,3S)-3-[(R)-1-(tert-butyl-dimethyl-silanyloxy)-ethyl]-2-[2-(tert-butyl-diphenyl-silanyloxy)-acetylsulfanyl]-4-oxo-azetidin-1-yl}-2-hydroxy-acetoxymethyl ester