Ammonium Chloride → tert-butyl (2R)-2-(tert-butyldimethylsilyloxy)-4-(3-fluorophenyl)-4-hydroxybutylcarbamate

HRID 513003Notes

Reaction equation

HRID 513003 reaction equation
[Si:1]([O:8][C@H:9]1[CH2:13][N:12]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])[C:11](=[O:21])[CH2:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].[F:22][C:23]1[CH:24]=[C:25]([Mg]Br)[CH:26]=[CH:27][CH:28]=1.[BH4-].[Na+].[NH4+].[Cl-]>C1COCC1.CO>[Si:1]([O:8][C@H:9]([CH2:10][CH:11]([C:27]1[CH:26]=[CH:25][CH:24]=[C:23]([F:22])[CH:28]=1)[OH:21])[CH2:13][NH:12][C:14](=[O:15])[O:16][C:17]([CH3:20])([CH3:19])[CH3:18])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]

Participants

7

Reactant 4

HCID 25517Ammonium ChlorideHCID 4311764Sodium borohydrideHCID 11220792(R)-1-Boc-4-[(tert-butyldimethylsilyl)oxy]pyrrolidin-2-oneHCID 178505773HCID 178505773, compound

Product 1

HCID 66684244tert-butyl (2R)-2-(tert-butyldimethylsilyloxy)-4-(3-fluorophenyl)-4-hydroxybutylcarbamate

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
0 °C

Procedure

To a solution of (R)-tert-butyl 4-(tert-butyldimethylsilyloxy)-2-oxopyrrolidine-1-carboxylate (I-1) (13.6 g, 43.2 mmol) in THF (100 mL) at 0° C. under N2 was added (3-fluorophenyl)magnesium bromide (52 mL of 1 M solution in THF, 51.84 mmol) over 1 hour. The reaction mixture was stirred at 0° C. for 1 hour. Methanol (80 mL) was added to the mixture followed by NaBH4 (2.45 g, 64.8 mmol) at 0° C. The mixture was stirred at 0° C. for 1 hour then poured into 10% aqueous NH4Cl. The mixture was extracted with EtOAc, washed with brine, dried over sodium sulfate, filtered and concentrated. The crude product was purified by column chromatography on silica gel with EtOAc/hexanes gradient as eluant to yield tert-butyl (2R)-2-(tert-butyldimethylsilyloxy)-4-(3-fluorophenyl)-4-hydroxybutylcarbamate (I-2). 1H NMR (400 MHz, CDCl3) δ 7.33-7.28 (m, 1 H), 7.13-7.09 (m, 2 H), 6.98-6.92 (m, 1 H), 4.97-4.90 (m, 1 H), 4.82 (bs, 1 H), 4.12-4.06 (m, 1 H), 3.42-3.33 (m, 1 H), 3.22-3.17 (m, 1 H), 1.88-1.84 (m, 2 H), 1.47 (s, 9 H), 0.93 (s, 9 H), 0.11 (s, 6 H). MS m/z 436.1 (M+23)+.

Workup

  1. stirringThe mixture was stirred at 0° C. for 1 hour
  2. extractionThe mixture was extracted with EtOAc
  3. washwashed with brine
  4. dry with materialdried over sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated
  7. customThe crude product was purified by column chromatography on silica gel with EtOAc/hexanes gradient as eluant

Sources & evidence

ORD record
ord-6bdf280a01c549f3a51333b916093385
Source dataset
uspto-grants-2015_08
Patent number
US09102671B2

Reaction notes

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