N-Fluorobenzenesulfonimide → tert-butyl 4-chloro-3-fluoro-5-methyl-1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-pyrrole-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

tert-butyl 3-bromo-4-chloro-5-methyl-1-{[2-(trimethylsilyl)ethoxy]methyl}-1H-pyrrole-2-carboxylate (Intermediate 265, 480 mg, 1.13 mmol) was dissolved in dry THF (8 ml), cooled down to −78° C., n-BuLi (2.5M in Hexane, 3.39 mmol) was added dropwise into the mixture via syringe and the mixture was stirred at −78° C. for 30 min followed by a quick addition of N-Fluorobenzensulfonimide (1.25 g, 3.96 mmol in 5 ml of THF/Toluene 1:1), the resulting mixture was then stirred at −78° C. for 30 min and slowly warmed up to room temperature during a period of 12 hrs. The reaction was quenched at 0° C. with drops of saturated NH4Cl solution and further diluted with EtOAc (50 ml). The organic phase was washed with brine and dried over anhydrous MgSO4, concentrated to an oil and purified by flash column chromatography eluted with 10% EtOAc in Hexanses. The desired product was obtained as an oil (125 mg).

Provenance & Evidence