Lithium Hexamethyldisilazide → tert-Butyl {(3S,5S)-5-(2,3-difluorophenyl)-2-oxo-1-[(2S)-3,3,3-trifluoro-2-hydroxypropyl]piperidin-3-yl}carbamate

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Reaction Conditions

Reaction Steps

To a pre-cooled −30° C. solution of tert-butyl[(3S,5S)-5-(2,3-difluorophenyl)-2-oxopiperidin-3-yl]carbamate (described in Intermediate 11, step B, 56 mg, 0.172 mmol) in tetrahydrofuran:N-methyl-2-pyrrolidinone (2:1, 0.8 mL) was added lithium bis(trimethylsilyl)amide (0.22 mL, 0.22 mmol, 1 M in THF) and the mixture was stirred at −30° C. for 30 min. (2S)-2-(Trifluoromethyl)oxirane (19 mg, 0.172 mmol) was added and the resulting mixture was stirred at −30° C. for 2 h. The mixture was diluted with water and extracted with ethyl acetate (3×). The combined organic extracts were washed with water, brine, dried over sodium sulfate, filtered and concentrated. Purification by silica gel chromatography (0% ethyl acetate→90% ethyl acetate/hexane) afforded the title compound. MS: m/z=461.2 (M+Na).

Provenance & Evidence