Triphenylphosphine → Diethyl 1-((3R,4S)-4-((tert-butoxycarbonyl)amino)tetrahydrofuran-3-yl)-3-iodo-1H-pyrazole-4,5-dicarboxylate

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Reaction Steps

To a solution of PPh3 (2.72 g, 10.35 mmol) in THF (10 mL) at 0° C. was added DIAD (2.013 mL, 10.35 mmol) dropwise and stirred for 15 min. A solution of Intermediate 104C (1.4 g, 4.14 mmol) in THF (10 mL) was added to the above reaction mixture and was stirred at 0° C. for 45 min. A solution of tert-butyl ((3S,4R)-4-hydroxytetrahydrofuran-3-yl)carbamate (1.683 g, 8.28 mmol) in THF (10 mL) was added dropwise at 0° C. and the reaction mixture was stirred at RT for 12 h. The reaction mixture was then concentrated and the crude compound was purified by silica gel chromatography (24 g REDISEP® column, eluting with 30% EtOAc in hexanes). Fractions containing the product were combined and evaporated to afford Intermediate 352A (1.7 g, 81%) as a white solid. MS(ES): m/z=522 [M−H]+; The crude product was taken to the next step without further purification.

Provenance & Evidence