Methanol → (S)-N-((R)-4-(3,4-dichlorophenyl)butan-2-yl)-2-methylpropane-2-sulfinamide

Temperature

75 °C

To a stirred solution of (S)-2-methylpropane-2-sulfinamide (373 mg, 3.08 mmol) and Intermediate 4A (700 mg, 3.22 mmol) in THF (2 mL) at rt was added tetraethoxytitanium (1.22 mL, 5.86 mmol). The reaction mixture was heated at 75° C. for 16 h, and allowed to cool and stay at rt for 72 h. Another equivalent of Ti(OEt)4 (1.22 mL, 5.86 mmol) and (S)-2-methylpropane-2-sulfinamide (373 mg, 3.08 mmol) were added. The reaction mixture was heated at 75° C. for 16 h before cooled down. This THF solution was stirred in a round-bottomed flask under argon at −40 to −50° C. L-Selectride (2016 μL, 2.016 mmol) was added dropwise. The resulting mixture was then warmed up to 0° C. during a 1.5 h period. It was cooled in dry ice and MeOH was added dropwise until gas evolution stopped. The mixture was stirred at rt for 20 min. It was filtered through Celite and rinsed with CH2Cl2 and the filtrate was washed with brine (2×) and dried over Na2SO4, filtered and concentrated. The residue was purified on flash chromatography (0-100% hexanes/EtOAc) to give Intermediate 4B (620 mg, 1.92 mmol, 59.6% yield) as slightly tan oil (slow eluent) and an impure (S)—N—((S)-4-(3,4-dichlorophenyl)butan-2-yl)-2-methylpropane-2-sulfinamide. LC-MS (ESI) m/z 322.0 (M+H), RT=2.34 min (Method B).

1. temperatureto cool
2. temperatureThe reaction mixture was heated at 75° C. for 16 h
3. temperaturebefore cooled down
4. temperatureThe resulting mixture was then warmed up to 0° C. during a 1.5 h period
5. filtrationIt was filtered through Celite
6. washrinsed with CH2Cl2
7. washthe filtrate was washed with brine (2×)
8. dry with materialdried over Na2SO4
9. filtrationfiltered
10. concentrationconcentrated
11. customThe residue was purified on flash chromatography (0-100% hexanes/EtOAc)

ORD record

ord-217f816cc8bf4397aac746204a48c4ab

Source dataset

uspto-grants-2016_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09394260B2