Isobutyl chloroformate → HCID 57947852, compound

HRID 340979Notes

Reaction equation

HRID 340979 reaction equation
[C:1]([O:5][C:6]([NH:8][C@H:9]([CH2:17][O:18][Si:19]([C:22]([CH3:25])([CH3:24])[CH3:23])([CH3:21])[CH3:20])[CH2:10][C:11]([CH3:16])([CH3:15])[C:12](O)=[O:13])=[O:7])([CH3:4])([CH3:3])[CH3:2].ClC(OCC(C)C)=O.[BH4-].[Na+]>C1COCC1.O>[Si:19]([O:18][CH2:17][C@@H:9]([NH:8][C:6](=[O:7])[O:5][C:1]([CH3:4])([CH3:3])[CH3:2])[CH2:10][C:11]([CH3:15])([CH3:16])[CH2:12][OH:13])([C:22]([CH3:23])([CH3:24])[CH3:25])([CH3:21])[CH3:20]

Participants

6

Reactant 3

HCID 62365Isobutyl chloroformateHCID 4311764Sodium borohydrideHCID 57947353HCID 57947353, compound

Product 1

HCID 57947852HCID 57947852, compoundYield 83.1%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
2.5 °C

Procedure

To a solution of (S)-4-(tert-butoxycarbonylamino)-5-(tert-butyldimethylsilyloxy)-2,2-dimethylpentanoic acid (2.5 g, 6.7 mmol) and TEA (1.9 mL, 13.4 mmol) in THF (50 mL) was added isobutyl chloroformate (1.1 mL, 8.04 mmol) at 0-5° C. The reaction mixture was stirred at 0-5° C. for 15 min and filtered. To the filtrate was added a suspension of NaBH4 (0.5 g, 13.4 mmol) in water (5 mL) at 0-5° C. The reaction mixture was stirred at 0-5° C. for 30 min, quenched with saturated NH4Cl solution, and extracted with EtOAc (200 mL). The organic layer was washed with water and brine, dried over Na2SO4, filtered, and concentrated. The residue was purified on silica gel column using a mixture of EtOAc and hexanes to give (S)-tert-butyl 1-(tert-butyldimethylsilyloxy)-5-hydroxy-4,4-dimethylpentan-2-ylcarbamate (2.0 g, 83.1%). LRMS (M+H+-Boc) m/z 262.2.

Workup

  1. filtrationfiltered
  2. additionTo the filtrate was added
  3. stirringThe reaction mixture was stirred at 0-5° C. for 30 min
  4. customquenched with saturated NH4Cl solution
  5. extractionextracted with EtOAc (200 mL)
  6. washThe organic layer was washed with water and brine
  7. dry with materialdried over Na2SO4
  8. filtrationfiltered
  9. concentrationconcentrated
  10. customThe residue was purified on silica gel column
  11. additiona mixture of EtOAc and hexanes

Sources & evidence

ORD record
ord-339c2fbdf1ef422e9d6b6596a3cfb5ee
Source dataset
uspto-grants-2014_11
Patent number
US08895582B2

Reaction notes

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