Diisopropylethylamine → (2S,5S)-1-tert-butyl 2-(3-chloro-8-oxo-8,9,10,11-tetrahydro-5H-dibenzo[c,g]chromen-9-yl) 5-methylpyrrolidine-1,2-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of 9-bromo-3-chloro-10,11-dihydro-5H-dibenzo[c,g]chromen-8(9H)-one (1.41 g, 3.88 mmol) in MeCN (17 mL) was added (2S,5S)-1-(tert-butoxycarbonyl)-5-methylpyrrolidine-2-carboxylic acid (980 mg, 4.27 mmol) and DIPEA (1.49 mL, 8.54 mmol). After stirring for 18 h at 50° C., the solution was diluted with EtOAc and washed successively with 1N HCl, saturated aqueous NaHCO3 and brine. The organics were dried over Na2SO4, filtered and concentrated under reduced pressure. The crude residue was purified by silica column chromatography (10% to 30% EtOAc/hexanes) to afford (2S,5S)-1-tert-butyl 2-(3-chloro-8-oxo-8,9,10,11-tetrahydro-5H-dibenzo[c,g]chromen-9-yl) 5-methylpyrrolidine-1,2-dicarboxylate (1.63 g, 81%).

Provenance & Evidence