2,6-Lutidine → 5-(Tert-butyl-dimethyl-silanyloxy)-3-methyl-1h-pyrrole-2-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

tert-Butyldimethylsilyltrifluoromethanesulfonate (9.99 ml, 11.49 g, 43.5 mmol, 3.0 equiv) was added to a stirring solution of 3-methyl-5-oxo-2,5-dihydro-pyrrole-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (3.7 g, 14.5 mmol, 1.0 equiv) and 2,6-lutidine (5.07 ml, 4.66 g, 43.5 mmol, 3.0 equiv) in dichloromethane (100 ml) at 23° C. The mixture was stirred at 23° C. for 15 h, then washed with pH=7 buffer solution (30 ml). The aqueous layer was extracted with two 40 ml portions of dichloromethane. The combined organic layers were dried over sodium sulfate. The solids were filtered and the filtrate was concentrated. The residue was purified by flash column chromatography (3% ethyl acetate-hexanes initially, grading to 6% ethyl acetate-hexanes) to afford 5-(tert-Butyl-dimethyl-silanyloxy)-3-methyl-1H-pyrrole-2-carboxylic acid methyl ester (3.46 g, 89%) as a yellow oil.

Provenance & Evidence