反应详情

tert-Butyldimethylsilyltrifluoromethanesulfonate (2.40 ml, 2.75 g, 10.4 mmol, 2.0 equiv) was added dropwise over 8 min to a stirring solution of 5-(tert-butyl-dimethyl-silanyloxy)-3-methyl-1H-pyrrole-2-carboxylic acid methyl ester (1.4 g, 5.2 mmol, 1.0 equiv) and cyclohexanecarbaldehyde (0.94 ml, 0.87 g, 7.8 mmol, 1.5 equiv) in dichloromethane (100 ml) at −78° C. The resultant solution was stirred at −78° C. for 2 h, then pH=7 buffer solution (50 ml) was added. The organic layer was washed with brine solution (50 ml), and dried over sodium sulfate. The solids were filtered and the filtrate was concentrated. The residue obtained was purified by flash column chromatography (5% ethyl acetate-dichloromethane initially, grading to 8% ethyl acetate-dichloromethane, then to 10% ethyl acetate-dichloromethane) to give 2-[(tert-butyl-dimethyl-silanyloxy)-cyclohexyl-methyl]-3-methyl-5-oxo-2,5-dihydro-1H-pyrrole-2-carboxylic acid methyl ester (1.69 g, 85%) as a colorless oil.

1. washThe organic layer was washed with brine solution (50 ml)
2. dry with materialdried over sodium sulfate
3. filtrationThe solids were filtered
4. concentrationthe filtrate was concentrated
5. customThe residue obtained
6. customwas purified by flash column chromatography (5% ethyl acetate-dichloromethane initially