تفاعل #595318

معادلة التفاعل

(R)-(+)-2-bromo-3-methylbutyric acid

cesium thiobenzoate

→

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

المردود 72.6%

المذيبات

ether

DMF

ظروف التفاعل

المعالجة

1. 1
   غسيلwashed with H2O (4×40 mL)
2. 2
   تجفيفThe ethereal layer was dried (Na2SO4)
3. 3
   تركيزconcentrated
4. 4
   أخرىThe crude residue was recrystallized from hexanes

الإجراء التجريبي

To a solution of (R)-(+)-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 (S)-2-benzoylthio-3-methylbutanoic acid as a pale yellow solid (3.89 g, 72%); 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), 12.0 (br s, 1H); 13C NMR (75 MHz, CDCl3) δ 19.8, 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=−94.2 (c 1, CH2Cl2).

المصدر