Triethylamine → 1,1-Dimethylethyl 3-fluoro-4-[(methylsulfonyl)oxy]-1-piperidinecarboxylate

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Reaction Steps

A solution of tert-butyl 3-fluoro-4-hydroxypiperidine-1-carboxylate, 2.4 (63 g, 0.287 mol) in anhydrous methylene chloride (630 mL) was treated with triethylamine (60 mL, 0.43 μmol) followed by methane sulfonyl chloride (26.7 mL, 0.345 mol) at 0° C. under N2 atmosphere. The solution was allowed to warm slowly to ambient temperature and stirred for 14 hours. The mixture was partitioned between saturated NaHCO3 (400 mL) and methylene chloride (400 mL). The aqueous layer was extracted with methylene chloride (2×500 mL). The combined organic phases were washed with 1N HCl, brine, dried over Na2SO4, filtered and concentrated under vacuum. The residue was purified by silica gel chromatography, eluting with 20-30% EtOAc/Hexane to provide the tert-butyl 3-fluoro-4-((methylsulfonyl)oxy)piperidine-1-carboxylate, 2.5 (78 g, 91%). 1HNMR (CDCl3, 400 MHz): δ 4.98-4.86 (m, 1H), 4.80-4.74 (m, 0.5H), 4.67-4.63 (m, 0.5H), 3.92-3.45 (m, 3H), 3.44-3.25 (m, 1H), 3.08 (s, 3H), 2.20-2.07 (m, 1H), 1.93-1.80 (m, 1H), 1.45 (s, 9H).

Provenance & Evidence