Tributylphosphine → (S)-tert-butyl 4-(3-(4-bromo-2-fluoro-5-methylphenoxy)-2-oxopyrrolidin-1-yl)piperidine-1-carboxylate

Participants

Reaction Steps

Tributylphosphine (2.0 mL, 7.8 mmol) was added slowly to a degassed solution of di-tert-butyl diazene-1,2-dicarboxylate (1.8 g, 7.8 mmol) in dry THF (30 mL) at ambient temperature. The resulting mixture was stirred for 5 minutes, then added dropwise to a 0° C. solution of (S)-tert-butyl 4-(2-(4-bromo-2-fluoro-5-methylphenoxy)-4-hydroxybutanamido)piperidine-1-carboxylate (3.2 g, 6.5 mmol) in THF (30 mL). The reaction was allowed to stir at ambient temperature overnight. Another 1.2 equivalents of reagents (tributylphosphine, tert-butyl diazene-1,2-dicarboxylate, and THF, prepared in same fashion) was added to the reaction mixture, and the reaction was stirred overnight. The reaction was concentrated and purified over silica gel (35 to 50% EtOAc in hexanes) to afford (S)-tert-butyl 4-(3-(4-bromo-2-fluoro-5-methylphenoxy)-2-oxopyrrolidin-1-yl)piperidine-1-carboxylate (2.3 g, 4.9 mmol, 75% yield) as a white solid.

Provenance & Evidence