Ammonium Chloride → 1-tert-butyl 2-methyl (2S)-4-methylidenepyrrolidine-1,2-dicarboxylate

HRID 457906Notes

Reaction equation

[CH3:1]C(C)([O-])C.[K+].O=[C:8]1[CH2:12][N:11]([C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])[C@H:10]([C:20]([O:22][CH3:23])=[O:21])[CH2:9]1.[Cl-].[NH4+]>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C(OCC)C>[CH2:1]=[C:8]1[CH2:12][N:11]([C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])[C@H:10]([C:20]([O:22][CH3:23])=[O:21])[CH2:9]1

Participants

Conditions

Temperature: 35 °C

Procedure

Methyltriphenylphosphonium bromide (22 g, 61.6 mmol) was added to a solution of potassium tert-butoxide (6.5 g, 57.6 mmol) in anhydrous diethyl ether (450 ml) at 0° C. under nitrogen and the resulting bright yellow mixture stirred for 30 minutes. A solution of 1-tert-butyl 2-methyl (2S)-4-oxo-1,2-pyrrolidinedicarboxylate (10 g, 41.1 mmol in 150 ml anhydrous diethyl ether) was added slowly to the reaction mixture, which was then warmed at 35° C. for 3 h. Saturated aqueous ammonium chloride solution (0.5 ml) was then added. The organic layer was removed, and the aqueous washed with diethyl ether (3×5 ml). The combined organic layers were dried with brine and magnesium sulfate before filtering and removal of solvent. Silica gel chromatography, eluting with 15% ethyl acetate in hexanes gave the desired product 6.9 g (70% yield) as a off-white wax.

Workup

customThe organic layer was removed
washthe aqueous washed with diethyl ether (3×5 ml)
dry with materialThe combined organic layers were dried with brine and magnesium sulfate
filtrationbefore filtering
customremoval of solvent
washSilica gel chromatography, eluting with 15% ethyl acetate in hexanes

Sources & evidence

ORD record: ord-19c87251e75245ea9e9f5f7eeabef43b
Source dataset: uspto-grants-2007_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07189754B2

Reaction notes

Loading…