Cesium carbonate → (2S, 4S)-1-tert-butyl 2-(2-oxo-2-(8-oxo-8,9, 10,11-tetrahydro-5H-dibenzo[c,g]chromen-3-yl)ethyl) 4-(methoxymethyl)pyrrolidine-1,2-dicarboxylate

Participants

Reaction Steps

3-(2-Bromoacetyl)-10,11-dihydro-5H-dibenzo[c,g]chromen-8(9H)-one (7.47 g, 20.1 mmol) and (2S,4S)-1-(tert-butoxycarbonyl)-4-(methoxymethyl)pyrrolidine-2-carboxylic acid (5.22 g, 20.1 mmol) were suspended in 2-Me-THF (75 mL) and treated with Cs2CO3 (3.27 g, 10.1 mmol). After stirring 4 h at RT, the reaction mixture was diluted with DCM. The organic layer was washed with H2O. The aqueous layer was then back extracted 2× with DCM. The combined organics were dried over MgSO4, filtered and concentrated under reduced pressure. The crude residue was purified by silica column chromatography (10% to 50% EtOAc/DCM) to afford (2S, 4S)-1-tert-butyl 2-(2-oxo-2-(8-oxo-8,9, 10,11-tetrahydro-5H-dibenzo[c,g]chromen-3-yl)ethyl) 4-(methoxymethyl)pyrrolidine-1,2-dicarboxylate (7.73 g, 70%).

Provenance & Evidence