Phosphoric Acid → Tert-butyl ((2S,3S)-1-(benzyloxy)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)carbamate

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Reaction Steps

N-{(3S,4S)-2-oxo-1-(phenylmethoxy)-4-[(1,1,2,2-tetramethyl-1-silapropoxy)methyl]azetidin-3-yl}(tert-butoxy)carboxamide (2.80 g, 6.41 mmol) was dissolved in THF (50 mL) and pyridine (5 mL). Pyridine-hydrofluoride complex (4.0 mL, 2.6 eq of pyridine, 24 eq of HF) was added at −20° C. After 10 min, the mixture was warmed up at room temperature and stirred for 3.5 h. Phosphoric acid buffer (0.025 M, KH2PO4/Na2HPO4; ratio 1/1, 400 mL) was added and the resulting solution was extracted with ethyl acetate (3×100 mL). The organic phase was dried over Na2SO4 and the solvent was evaporated in vacuo. 2.04 g of the desired product was obtained and used for the next step.

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