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

HRID 1737185Notes

Reaction equation

HRID 1737185 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) δ 0.80-0.98 (m, 6H), 1.40-1.58 (m, 1H), 1.69-1.87 (m, 2H), 3.74 (s, 3H), 3.93-4.06 (m, 1H), 4.42 (d, 1H, J=12.0 Hz), 4.68-4.80 (m, 1H), 7.14-7.32 (m, 5H) 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-b560ab492b82401a98aecc4a17abf778
Source dataset
uspto-grants-1999_10
Patent number
US05962419

Reaction notes

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