Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → 4-tert-butoxycarbonylamino-3-(tert-butoxycarbonylamino-methyl)-but-2-enoic Acid Ethyl Ester

HRID 899782Notes

Reaction equation

[C:1]([O:5][C:6](=[O:20])[NH:7][CH2:8][C:9](=O)[CH2:10][NH:11][C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])([CH3:4])([CH3:3])[CH3:2].[C:21]([CH:26]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([O:23][CH2:24][CH3:25])=[O:22]>C1C=CC=CC=1>[CH2:24]([O:23][C:21](=[O:22])[CH:26]=[C:9]([CH2:10][NH:11][C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:8][NH:7][C:6]([O:5][C:1]([CH3:4])([CH3:3])[CH3:2])=[O:20])[CH3:25]

Participants

Conditions

Temperature: 45 °C

Procedure

To a solution of (3-tert-butoxycarbonylamino-2-oxo-propyl)-carbamic acid tert-butyl ester (310 mg, 1.08 mmol) in benzene (20 mL) was added (carbethoxymethylene)-triphenyl phosphorane (825 mg, 2.37 mmol) and the reaction mixture was stirred at 45° C. overnight. Then the mixture was cooled to room temperature and the solvent concentrated down. Purification by radical chromatography on silica gel (2 mm plate, using CH2Cl2) afforded the desired compound as a yellow oil (290 mg, 75%). 1H NMR (CDCl3) δ 1.26 (t, 3H, J=9.0 Hz), 1.42 (s, 18H), 3.87 (d, 2H, J=6.0 Hz), 4.09 (d, 2H, J=6.0 Hz), 4.15 (q, 2H, J=9.0 Hz), 5.34 (br s, 1H), 5.85 (s, 1H), 7.34 (s, 1H).

Workup

temperatureThen the mixture was cooled to room temperature
concentrationthe solvent concentrated down
customPurification by radical chromatography on silica gel (2 mm plate, using CH2Cl2)

Sources & evidence

ORD record: ord-932ed7523fe948caaead865253a96378
Source dataset: uspto-grants-2008_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07354934B2

Reaction notes

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