Cornforth reagent → 1-tert-Butyl 2-methyl (2R)-4-oxopyrrolidine-1,2-dicarboxylate

HRID 1408910Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1408910
[Cr](O[Cr]([O-])(=O)=O)([O-])(=O)=O.[NH+]1C=CC=CC=1.[NH+]1C=CC=CC=1.[OH:22][C@H:23]1[CH2:27][N:26]([C:28]([O:30][C:31]([CH3:34])([CH3:33])[CH3:32])=[O:29])[C@@H:25]([C:35]([O:37][CH3:38])=[O:36])[CH2:24]1>ClCCl>[O:22]=[C:23]1[CH2:27][N:26]([C:28]([O:30][C:31]([CH3:32])([CH3:33])[CH3:34])=[O:29])[C@@H:25]([C:35]([O:37][CH3:38])=[O:36])[CH2:24]1

Komponenten

4

Edukt 2

HCID 2724130Cornforth reagentHCID 6951202(2R,4R)-4-Hydroxy-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

Produkt 1

HCID 105381811-tert-Butyl 2-methyl (2R)-4-oxopyrrolidine-1,2-dicarboxylateAusbeute 131 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 6344DichloromethaneLösungsmittel

Versuchsvorschrift

To slurry of pyridinium dichromate (9.97 g, 26.5 mmol) in dichloromethane (60 mL) at rt was added (2R,4R)-1-tert-butyl 2-methyl 4-hydroxypyrrolidine-1,2-dicarboxylate (5.00 g, 20.39 mmol) in several portions. The resulting mixture was stirred overnight at rt. Celite (5 g) was added and the mixture stirred for 40 min, filtered and the filter cake was rinsed with additional dichloromethane (50 mL×3). The resulting filtrate was concentrated and toluene (40 mL) was added followed by concentration again under vacuum to give ˜6.5 g of a brown syrup as the crude product. Purification by flash silica gel chromatography (120 g column, EtOAc in Hexane, 0 to 100% gradiant, 85 mL/min) afforded 4.18 g (84%) of the title compound as a white solid. LCMS (condition A): m/z 144 (M-Boc) −ve. 1H NMR (400 MHz, CDCl3) δ ppm 4.64-4.89 (1 H, m), 3.84-3.96 (2 H, m), 3.77 (3 H, s), 2.81-3.10 (1 H, m), 2.59 (1 H, dd, J=18.93, 1.76 Hz), 1.52 (9 H, s).

Aufarbeitung

  1. additionCelite (5 g) was added
  2. stirringthe mixture stirred for 40 min
  3. filtrationfiltered
  4. washthe filter cake was rinsed with additional dichloromethane (50 mL×3)
  5. concentrationThe resulting filtrate was concentrated
  6. additiontoluene (40 mL) was added
  7. concentrationfollowed by concentration again under vacuum

Quellen und Nachweise

ORD-Eintrag
ord-990fe9ec1d174545930ea8e5f37ee126
Quelldatensatz
uspto-grants-2014_12
Patentnummer
US08921368B2

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