Ammonium Chloride → (R)-tert-butyl 3-((S)-1-(benzo[b]thiophen-2-yl)-1-hydroxy-5-methoxypentyl)piperidine-1-carboxylate

Participants

Reaction Steps

A solution of (R)-tert-butyl 3-(benzo[b]thiophene-2-carbonyl)piperidine-1-carboxylate (146 mg, 0.423 mmol) in dry THF (5 mL) was cooled to −70° C. A solution of 1.34 M 4-methoxybutylmagnesium chloride in THF (630 μL, 2 equiv) was added slowly. After 10 min, the reaction mixture was allowed to warm up to rt slowly and stirred for another 2 h. Sat'd aq NH4Cl (20 mL) was added and the mixture was extracted with ether (2×40 mL). The combined ether layers were washed with brine (20 mL) and dried over Na2SO4. After concentration, the crude product was purified by chromatography on a 12-g silica cartridge eluted with a gradient from 0 to 35% EtOAc in hexanes to afford (R)-tert-butyl 3-((S)-1-(benzo[b]thiophen-2-yl)-1-hydroxy-5-methoxypentyl)piperidine-1-carboxylate (160.7 mg, 88%).

Provenance & Evidence