Ethanol → benzyl ((1S)-2-{[tert-butyl(dimethyl)silyl]oxy}-4-hydroxy-1-isopropylbutyl)carbamate

HRID 906957Notes

Reaction equation

HRID 906957 reaction equation
[CH2:1]([O:8][C:9]([NH:11][C@@H:12]([CH:28]([CH3:30])[CH3:29])[CH:13]([O:20][Si:21]([C:24]([CH3:27])([CH3:26])[CH3:25])([CH3:23])[CH3:22])[CH2:14][C:15](OCC)=[O:16])=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Cl-].[Ca+2].[Cl-].[BH4-].[Na+].C(O)C>C1COCC1.C(OCC)(=O)C>[Si:21]([O:20][CH:13]([CH2:14][CH2:15][OH:16])[C@@H:12]([NH:11][C:9](=[O:10])[O:8][CH2:1][C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1)[CH:28]([CH3:30])[CH3:29])([C:24]([CH3:27])([CH3:26])[CH3:25])([CH3:23])[CH3:22]

Participants

7

Reactant 4

HCID 702EthanolHCID 4311764Sodium borohydrideHCID 5284359Calcium ChlorideHCID 67390315ethyl (4S)-4-{[(benzyloxy)carbonyl]amino}-3-{[tert-butyl(dimethyl)silyl]oxy}-5-methylhexanoate

Product 1

HCID 86640708benzyl ((1S)-2-{[tert-butyl(dimethyl)silyl]oxy}-4-hydroxy-1-isopropylbutyl)carbamateYield 93.1%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolvent

Procedure

Under an argon atmosphere, to a suspension (303 mL) of ethyl (4S)-4-{[(benzyloxy)carbonyl]amino}-3-{[tert-butyl(dimethyl)silyl]oxy}-5-methylhexanoate (17.7 g), calcium chloride (6.73 g) and sodium borohydride (4.58 g) in dehydrated THF was added with stirring under ice-cooling dehydrated ethanol (152 mL), and the mixture was gradually warmed to room temperature and stirred for 15 hr. The reaction mixture was slowly poured into a mixture of ethyl acetate and ice water (containing 1 mol/L hydrochloric acid, 122 mL) and the mixture was partitioned. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated. The residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=19/1→1/1) to give benzyl ((1S)-2-{[tert-butyl(dimethyl)silyl]oxy}-4-hydroxy-1-isopropylbutyl)carbamate as colorless oil (yield: 14.9 g).

Workup

  1. stirringstirred for 15 hr
  2. customthe mixture was partitioned
  3. washThe organic layer was washed with saturated brine
  4. dry with materialdried over anhydrous magnesium sulfate
  5. concentrationconcentrated
  6. customThe residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=19/1→1/1)

Sources & evidence

ORD record
ord-2c36faa00f764cba848ee15c192bd6ec
Source dataset
uspto-grants-2011_09
Patent number
US08013008B2

Reaction notes

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