Trifluoromethanesulfonic acid → methyl(2S)-2-benzoxy-4-methylpentanoate

HRID 1858871Notes

Reaction equation

HRID 1858871 reaction equation
[OH:1][C@@H:2]([CH2:7][CH:8]([CH3:10])[CH3:9])[C:3]([O:5][CH3:6])=[O:4].ClC(Cl)(Cl)C(=N)O[CH2:15][C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1.FC(S(O)(=O)=O)(F)F>C(Cl)Cl>[CH2:15]([O:1][C@@H:2]([CH2:7][CH:8]([CH3:10])[CH3:9])[C:3]([O:5][CH3:6])=[O:4])[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1

Participants

5

Reactant 3

HCID 62406Trifluoromethanesulfonic acidHCID 144968Benzyl 2,2,2-trichloroacetimidateHCID 9989388Methyl (2S)-2-hydroxy-4-methylpentanoate

Product 1

HCID 57145336methyl(2S)-2-benzoxy-4-methylpentanoateYield 74.7%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a stirred solution of methyl (2S)-2-hydroxy-4-methylpentanoate (0.5 g, 3.4 mmol) in anhydrous CH2Cl2 (10 mL) at R.T. under Ar was added benzyl 2,2,2-trichloroacetimidate (1.4 mL, 6.8 mmol) and trifluoromethylsulfonic acid (25 μl). After 30 min the reaction mixture was taken up in CH2Cl2 (20 mL). The organic layer was washed with sat. NaCl (2×10 mL), 1 N HCl (2×10 mL), sat. NaCl (2×10 mL), dried (MgSO4), filtered and concentrated. Purification by flash chromatography on silica gel (EA:H; 1:10) afforded methyl (2S)-2-benzoxy-4-methylpentanoate as an oil (0.6 g, 73.5%): 1H NMR (CDCl3, 300 MHz) δ0.80-0.98 (m, 6 H), 1.40-1.58 (m, 1 H), 1.69-1.87 (m, 2 H), 3.74 (s, 3 H), 3.93-4.06 (m, 1 H), 4.42 (d, 1 H, J=12.0 Hz), 4.68-4.80 (m, 1 H), 7.14-7.32 (m, 5 H) ppm.

Workup

  1. washThe organic layer was washed with sat. NaCl (2×10 mL), 1 N HCl (2×10 mL), sat. NaCl (2×10 mL)
  2. dry with materialdried (MgSO4)
  3. filtrationfiltered
  4. concentrationconcentrated
  5. customPurification by flash chromatography on silica gel (EA:H; 1:10)

Sources & evidence

ORD record
ord-1561802ad1f74ae6818e38c6814dad08
Source dataset
uspto-grants-2000_11
Patent number
US06153171

Reaction notes

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