Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → (R)-ethyl 3-(N-benzyloxycarbonylpyrrolidin-2-yl)-2-propenoate

HRID 1935608Notes

Reaction equation

HRID 1935608 reaction equation
[C:1]([N:11]1[CH2:15][CH2:14][CH2:13][CH:12]1[CH:16]=O)([O:3][CH2:4][C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)=[O:2].[C:18]([CH:23]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([O:20][CH2:21][CH3:22])=[O:19]>O1CCCC1>[CH2:4]([O:3][C:1]([N:11]1[CH2:15][CH2:14][CH2:13][C@@H:12]1[CH:16]=[CH:23][C:18]([O:20][CH2:21][CH3:22])=[O:19])=[O:2])[C:5]1[CH:6]=[CH:7][CH:8]=[CH:9][CH:10]=1

Participants

4

Reactant 2

HCID 70670Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl esterHCID 11064320Benzyl 2-formylpyrrolidine-1-carboxylate

Product 1

HCID 53843981(R)-ethyl 3-(N-benzyloxycarbonylpyrrolidin-2-yl)-2-propenoate

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a stirred solution of N-carbobenzyloxypyrrolidine-2-carboxaldehyde (1.17 g, 5.00 mmol) in anhydrous tetrahydrofuran at −78° C. was added (carboethoxymethylene)-triphenylphosphorane (2.09 g, 6.00 mmol. 1.2 eq) as a solid portionwise. The resulting reaction mixture was stirred at room temperature under nitrogen for 2 hours, and then heated at reflux under nitrogen for 1 hour. The reaction mixture was evaporated under reduced pressure and the residue was column chromatographed using silica gel (approximately 100 g) and elution with 20% diethyl ether in hexanes to afford the title compound as a clear, colorless oil (1.11 g, 3.65 mmol, 73%): 1H NMR (CDCL3−d8) δ 7.34-7.25 (m, 5H), 6.89-6.76 (m, 1H), 5.88-5.74 (m, 1H), 5.18-5.05 (m, 2H), 4.60-4.43 (m, 1H), 4.17 (qu, J=7.1 Hz, 2H), 3.55-3.40 (m, 2H), 2.11-2.00 (m, 1H), 1.90-1.75 (m, 3H), 1.28 (t, J=7.1 Hz, 3H); 13C NMR (CDCl3) [Note: due to slow nitrogen inversion two conformers of the products are seen by NMR spectroscopy]δ 166.3, 154.7, 147.9, 147.4, 136.6, 128.4, 127.9, 120.9, 66.9, 65.8, 60.4, 58.1, 57.7, 46.8, 46.4, 31.6, 30.8, 23.6, 22.8, 22.6, 15.3, 14.2.

Workup

  1. customThe resulting reaction mixture
  2. temperatureheated
  3. temperatureat reflux under nitrogen for 1 hour
  4. customThe reaction mixture was evaporated under reduced pressure
  5. customchromatographed
  6. washsilica gel (approximately 100 g) and elution with 20% diethyl ether in hexanes

Sources & evidence

ORD record
ord-46698219fa3647668ad8f95dea6008fb
Source dataset
uspto-grants-2002_05
Patent number
US06387941B1

Reaction notes

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