反应详情

温度

-78 °C

Lithium diisopropylamide solution (0.695 M solution in tetrahydrofuran, 5.66 ml, 3.93 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 (1.5 g, 3.93 mmol, 1.0 equiv) in tetrahydrofuran (45 ml) at −78° C. The reaction mixture was stirred at −78° C. for 30 min. Chlorotrimethylsilane (0.5 ml, 427 mg, 3.93 mmol, 1.0 equiv) was added and the resultant solution was stirred at −78° C. for 3 h. Another equiv of lithium diisopropylamide solution (0.695 M solution in tetrahydrofuran, 5.66 ml, 3.93 mmol, 1.0 equiv) was added dropwise at −78° C. The reaction mixture was stirred −78° C. for 30 min. Allyl bromide (0.68 ml, 0.951 g, 7.86 mmol, 2.0 equiv) was added dropwise via syringe at −78° C. The reaction mixture was stirred at −78° C. for 2 h. A buffer solution (pH=7, 100 ml) was added at −78° C. The mixture was extracted with ethyl acetate (50 ml×3). The combined organic layers were 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 4-allyl-2-[(tert-butyl-dimethyl-silanyloxy)-cyclohexyl-methyl]-3-methylene-5-oxo-pyrrolidine-2-carboxylic acid methyl ester (0.757 g, 46%) as a white solid.

1. stirringThe reaction mixture was stirred −78° C. for 30 min
2. stirringThe reaction mixture was stirred at −78° C. for 2 h
3. extractionThe mixture was extracted with ethyl acetate (50 ml×3)
4. dry with materialThe combined organic layers were dried over sodium sulfate
5. filtrationthe solids were filtered
6. concentrationThe filtrate was concentrated
7. customThe residue was purified by flash column chromatography (10% ethyl acetate-hexanes initially