2,6-Lutidine → 3-Methyl-5-oxo-2,5-dihydro-pyrrole-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of tert-butoxycarbonylamino-(dimethoxy-phosphoryl)-acetic acid methyl ester (20.0 g, 67 mmol, 1 equiv), 2,2,6-trimethyl-[1,3]dioxin-4-one (43.96 ml, 47.8 g, 336 mmol, 5.0 equiv), and 2,6-lutidine (11.71 ml, 10.77 g, 101 mmol, 1.5 equiv) in toluene (200 ml) was heated at reflux for 16 h. The reaction mixture was allowed to cool to 23° C. and was concentrated. The residue was purified by flash column chromatography (5% ethyl acetate-dichloromethane initially, grading to 8% ethyl acetate-dichloromethane) to give 3-methyl-5-oxo-2,5-dihydro-pyrrole-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (14.74 g, 86%) as a yellow oil.

Provenance & Evidence