Water → (4S,6R)-6-methyl-7-((R)-1-phenylethyl)-1-oxa-7-azaspiro[3.5]nonane

Temperature

60 °C

To a solution of trimethylsulfoxonium iodide (10.1 g, 46.0 mmol) in t-BuOH (anhydrous, 10 mL) was added tBuOK (1M in t-BuOH, 36.8 mL, 36.8 mmol) and the resulting mixture was stirred at 60° C. for 1 h. Then a solution of (R)-2-methyl-1-((R)-1-phenylethyl)piperidin-4-one (2 g, 9.20 mmol) in t-BuOH (6 mL) was added slowly. The reaction mixture was heated at 60° C. for 72 h, then cooled to room temperature and poured into water. The aqueous phase was extracted with EtOAc (2×). The organic phases were combined, washed with brine, dried over Na2SO4, filtered and concentrated. The resulting residue was purified by silica gel flash chromatography (0-30% EtOAc/heptanes) to provide the desired isomer (4S,6R)-6-methyl-7-((R)-1-phenylethyl)-1-oxa-7-azaspiro[3.5]nonane as a colorless oil (0.67 g, 30%). 1H NMR (400 MHz, CD2Cl2) δ ppm 7.48 (d, J=7.83 Hz, 2H), 7.34 (t, J=7.58 Hz, 2H), 7.24 (t, J=6.82 Hz, 1H), 4.39-4.51 (m, 2H), 4.25 (q, J=6.74 Hz, 1H), 2.78-3.01 (m, 1H), 2.30-2.45 (m, 3H), 2.21-2.30 (m, 1H), 2.13 (td, J=2.56, 13.07 Hz, 1H), 1.85-1.95 (m, 1H), 1.44-1.62 (m, 2H), 1.28 (d, J=6.82 Hz, 3H), 1.20 (d, J=6.32 Hz, 3H).

1. temperatureThe reaction mixture was heated at 60° C. for 72 h
2. temperaturecooled to room temperature
3. extractionThe aqueous phase was extracted with EtOAc (2×)
4. washwashed with brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customThe resulting residue was purified by silica gel flash chromatography (0-30% EtOAc/heptanes)

ORD record

ord-34a72be321534adca4e7ad04a4912709

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08846656B2