alpha-Bromoisovaleric acid, (R)- → (S)-2-benzoylthio-3-methylbutanoic acid

HRID 508136Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 508136
Br[C@H:2]([CH:6]([CH3:8])[CH3:7])[C:3]([OH:5])=[O:4].[C:9]([O-:17])(=[S:16])[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1.[Cs+]>CN(C=O)C.CCOCC>[C:9]([S:16][C@@H:2]([CH:6]([CH3:8])[CH3:7])[C:3]([OH:5])=[O:4])(=[O:17])[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1

Komponenten

5

Edukt 2

HCID 156968alpha-Bromoisovaleric acid, (R)-HCID 23707493Cesium thiobenzoate

Produkt 1

HCID 57454456(S)-2-benzoylthio-3-methylbutanoic acidAusbeute 72,6 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 3283Diethyl EtherLösungsmittelHCID 6228DimethylformamideLösungsmittel

Versuchsvorschrift

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).

Aufarbeitung

  1. washwashed with H2O (4×40 mL)
  2. dry with materialThe ethereal layer was dried (Na2SO4)
  3. concentrationconcentrated
  4. customThe crude residue was recrystallized from hexanes

Quellen und Nachweise

ORD-Eintrag
ord-5f5bff0798034470b3f506fc65b38bb7
Quelldatensatz
uspto-grants-2015_08
Patentnummer
US09095565B2

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