t-Butylammonium fluoride → (2S)-2-{[(1S)-1-(4-bromophenyl)-2,2,2-trifluoroethyl]amino}-5,5,5-trifluoropentan-1-ol

Temperature

0 °C

n-BuLi (2.5 M in hexanes, 21.4 mL) was added dropwise to a stirred solution of 1,4-dibromobenzene (12.6 g) in dry diethyl ether (80 mL) at −30° C. and the reaction mixture was stirred for 30 minutes. A solution of (2S)-1-{[tert-butyl(dimethyl)silyl]oxy}-5,5,5-trifluoro-N-[(1E)-2,2,2-trifluoroethylidene]pentan-2-amine (3.75 g, 10.7 mmol) in dry diethyl ether (30 mL) was then added dropwise and the reaction mixture was allowed to warm to ambient temperature and stirred for 16 hours. The reaction mixture was then quenched with 100 mL of water. The organic phase was washed with brine, dried with magnesium sulfate, and filtered. The filtrate was concentrated by rotary evaporation to yield crude product which was purified by silica gel chromatography using 1% ethyl acetate in hexanes as eluant to yield (S)-[1-(4-bromophenyl)-2,2,2-trifluoro-ethyl]-[1-(tert-butyl-dimethyl-silanyloxymethyl)-4,4,4-trifluoro-butyl]-amine (1.8 g). (S)-[1-(4-Bromophenyl)-2,2,2-trifluoro-ethyl]-[1-(tert-butyl-dimethyl-silanyloxymethyl)-4,4,4-trifluoro-butyl]-amine was dissolved in THF (50 mL) and chilled to 0° C. and tert-butylammonium fluoride (10.6 mL, 1 M THF solution) was added dropwise. The reaction mixture was allowed to warm to ambient temperature and stirred for 4 hours. The reaction mixture was quenched with a saturated aqueous solution of ammonium chloride and then ethyl acetate was added and the mixture vigorously shaken. The organic layer was separated and washed two times with brine, dried with magnesium sulfate and filtered. The solvent was removed by rotary evaporation to yield a residue which was purified on SiO2 using a gradient of 20-25% ethyl acetate in hexanes as eluant to yield (2S)-2-{[(1S)-1-(4-bromophenyl)-2,2,2-trifluoroethyl]amino}-5,5,5-trifluoropentan-1-ol.

1. temperatureto warm to ambient temperature
2. customThe reaction mixture was quenched with a saturated aqueous solution of ammonium chloride
3. additionethyl acetate was added
4. stirringthe mixture vigorously shaken
5. customThe organic layer was separated
6. washwashed two times with brine
7. dry with materialdried with magnesium sulfate
8. filtrationfiltered
9. customThe solvent was removed by rotary evaporation
10. customto yield a residue which
11. customwas purified on SiO2 using a gradient of 20-25% ethyl acetate in hexanes as eluant

ORD record

ord-6985cd3b7e5f4ac6924ff42bfc7dc9bf

Source dataset

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08772336B2