Diisopropylethylamine → (2S,4S)-1-tert-butyl 2-(3-chloro-8-oxo-8,9,10,11-tetrahydro-5H-dibenzo[c,g]chromen-9-yl) 4-methylpyrrolidine-1,2-dicarboxylate

Participants

Reaction Steps

To a solution of 9-bromo-3-chloro-10,11-dihydro-5H-dibenzo[c,g]chromen-8(9H)-one (1.32 g, 3.63 mmol) in MeCN (40 mL) was added (2S,4S)-1-(tert-butoxycarbonyl)-4-methylpyrrolidine-2-carboxylic acid (1.0 g, 4.36 mmol) and DIPEA (0.7 mL, 3.99 mmol). After stirring for 18 h, the solution was diluted with EtOAc and washed successively with saturated aqueous NaHCO3 and brine. The organics were dried over MgSO4, filtered and concentrated under reduced pressure. The crude residue was purified by silica column chromatography (10% to 40% EtOAc/hexanes) to afford (2S,4S)-1-tert-butyl 2-(3-chloro-8-oxo-8,9,10,11-tetrahydro-5H-dibenzo[c,g]chromen-9-yl) 4-methylpyrrolidine-1,2-dicarboxylate (1.31 g, 70%).

Provenance & Evidence