Toluene → 2-[(Tert-butyl-dimethyl-silanyloxy)-cyclohexyl-methyl]-4-(2-chloro-ethyl)-3-methylene-5-oxo-pyrrolidine-2-carboxylic acid methyl ester

HRID 639869

Reaction equation

C([N-]C(C)C)(C)C.[Li+].[CH3:9][O:10][C:11]([C:13]1([CH:20]([O:27][Si:28]([C:31]([CH3:34])([CH3:33])[CH3:32])([CH3:30])[CH3:29])[CH:21]2[CH2:26][CH2:25][CH2:24][CH2:23][CH2:22]2)[C:17]([CH3:18])=[CH:16][C:15](=[O:19])[NH:14]1)=[O:12].Cl[Si](C)(C)C.[Cl:40][CH2:41][CH2:42]OS(C(F)(F)F)(=O)=O.C1(C)C=CC=CC=1>O1CCCC1>[CH3:9][O:10][C:11]([C:13]1([CH:20]([O:27][Si:28]([C:31]([CH3:34])([CH3:33])[CH3:32])([CH3:29])[CH3:30])[CH:21]2[CH2:26][CH2:25][CH2:24][CH2:23][CH2:22]2)[C:17](=[CH2:18])[CH:16]([CH2:42][CH2:41][Cl:40])[C:15](=[O:19])[NH:14]1)=[O:12]

Participants

Conditions

Temperature: -78 °C

Procedure

Lithium diisopropylamide solution (0.67 M solution in tetrahydrofuran, 0.09 ml, 0.06 mmol, 1.0 equiv) was added dropwise via syringe to a stirred solution of 2-[(tert-butyl-dimethyl-silanyloxy)-cyclohexyl-methyl]-3-methyl-5-oxo-2,5-dihydro-1H-pyrrole-2-carboxylic acid methyl ester (23 mg, 0.06 mmol, 1.0 equiv) in tetrahydrofuran (1.5 ml) at −78° C. The reaction mixture was stirred at −78° C. for 30 min. Chlorotrimethylsilane (8 μl, 6.8 mg, 0.06 mmol, 1.0 equiv) was added and the resultant solution was stirred at −78° C. for 2.5 h. Another equiv of lithium diisopropylamide solution (0.67 M solution in tetrahydrofuran, 0.09 ml, 0.06 mmol, 1.0 equiv) was added dropwise at −78° C. The reaction mixture was stirred −78° C. for 30 min. A stock solution of trifluoro-methanesulfonic acid 2-chloro-ethyl ester in toluene (2.45 M, 0.1 ml, 0.24 mmol, 4.0 equiv) was added dropwise via syringe at −78° C. The reaction mixture was stirred at −78° C. for 50 min. A buffer solution (pH=7, 5 ml) was added at −78° C. The organic layer was separated, washed with brine solution (5 ml), dried over sodium sulfate and the solids were filtered. The filtrate was concentrated. The residue was purified by flash column chromatography (10% ethyl acetate-hexanes initially, grading to 20% ethyl acetate-hexanes) to furnish 2-[(tert-butyl-dimethyl-silanyloxy)-cyclohexyl-methyl]-4-(2-chloro-ethyl)-3-methylene-5-oxo-pyrrolidine-2-carboxylic acid methyl ester (16 mg, 59%) along with recovered starting material (5 mg, 22%).

Workup

stirringThe reaction mixture was stirred −78° C. for 30 min
stirringThe reaction mixture was stirred at −78° C. for 50 min
customThe organic layer was separated
washwashed with brine solution (5 ml)
dry with materialdried over sodium sulfate
filtrationthe solids were filtered
concentrationThe filtrate was concentrated
customThe residue was purified by flash column chromatography (10% ethyl acetate-hexanes initially

Sources & evidence

ORD record: ord-76c624c744ae40d089f6380178feeb52
Source dataset: uspto-grants-2010_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07691896B2

Linked notes

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