반응 #496369

반응 방정식

(S)-(−)-2-bromo-3-methylbutyric acid

cesium thiobenzoate

→

(R)-2-benzoylthio-3-methylbutanoic acid

수율 75.5%

용매

ether

DMF

반응 조건

후처리

1. 1
   세척washed with H2O (4×40 mL)
2. 2
   건조The ethereal layer was dried (Na2SO4)
3. 3
   농축concentrated
4. 4
   기타The crude residue was recrystallized from hexanes

실험 절차

To a solution of (S)-(−)-2-bromo-3-methylbutyric acid (4.20 g, 23.2 mmol) in DMF (41 mL) was added cesium thiobenzoate (6.08 g, 22.5 mmol). The mixture was stirred at rt for 20 h. The resulting solution was diluted with ether (200 mL) and washed with H2O (4×40 mL). The ethereal layer was dried (Na2SO4), and concentrated. The crude residue was recrystallized from hexanes to afford (R)-2-benzoylthio-3-methylbutanoic acid as a pale yellow solid (4.05 g, 75%); 1H NMR (300 MHz, CDCl3) δ 1.09 (d, J=7.4 Hz, 3H), 1.11 (d, J=7.4 Hz, 3H), 2.40 (m, 1H), 4.37 (d, J=5.9 Hz, 1H), 7.45 (t, J=7.4 Hz, 2H), 7.57 (t, J=7.4 Hz, 1H), 7.97 (d, J=7.4 Hz, 2H), 11.9 (br s, 1H); 13C NMR (75 MHz, CDCl3) δ19.8, 20.6, 30.5, 53.1, 127.6, 128.8, 133.9, 136.3, 177.9, 190.3; IR (neat) 3100, 2967, 1709, 1669 cm−1; [α]D22=+95.6 (c 1, CH2Cl2). All spectral data was identical to that previously published (Strijtveen, B.; Kellogg, R. M. J. Org. Chem. 1986, 51, 3664).

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