Ammonium Chloride → HCID 67188901, compound

Participants

Reaction Steps

A solution of bromo-2-[(tert-butyl)dimethylsiloxy]benzene (2.1 g, 7.4 mmol) in Et2O (35 mL) was cooled to −78° C. and treated with 1.7 M tert-butyllithium in hexanes (8.6 mL, 15 mmol). The reaction was stirred for 30 min and a solution of (R)-tert-butyl 3-(N-methoxy-N-methylcarbamoyl)piperidine-1-carboxylate (1.0 g, 3.7 mmol) in Et2O was added slowly. The reaction was allowed to stir and warm to rt over a two-hour period. Saturated aq ammonium chloride was added to quench the reaction. The aq phase was extracted with Et2O three times. The combined organic layers were washed with brine and dried over MgSO4. The solvent was removed by evaporation and the crude product was purified by flash chromatography on silica gel eluting with EtOAc/hexanes to give a mixture of (2-tert-butyldimethylsiloxyphenyl)((R)—N-Boc-piperidin-3-yl)methanone and (2-hydroxyphenyl)((R)—N-Boc-piperidin-3-yl)methanone. A −20° C. solution of the crude mixture in tetrahydrofuran was treated with 1.3 M 4-methoxybutylmagnesium chloride in THF (14.9 mL, 19.4 mmol). The reaction was stirred and allowed to warm to rt over a two hour period. The reaction was quenched with ammonium chloride. The aq layer was extracted with Et2O. The combined organic layers were dried over MgSO4 and filtered. The solvent was evaporated and the crude product was purified by flash chromatography on silica gel eluting with EtOAc/hexanes to afford 2-((S)-1-hydroxy-5-methoxy-1-((R)—N-Boc-piperidin-3-yl)pentyl)[tertbutyldimethylsiloxy]benzene (874 mg, 47%) and 2-((S)-1-hydroxy-5-methoxy-1-((R)—N-Boc-piperidin-3-yl)pentyl)phenol (650 mg, 45%).

Provenance & Evidence