Cesium carbonate → HCID 59279949, compound

Participants

Reaction Steps

A suspension of 1-t-butyl 2-methyl (2S,4S)-4-{[(4-bromophenyl)sulfonyl]oxy}pyrrolidine-1,2-dicarboxylate (25.0 g, 53.8 mmol), the product of Step 3 (16.1 g, 53.8 mmol) and cesium carbonate (52.6 g, 162 mmol) in NMP (300 mL) was stirred at 75° C., under nitrogen, for 2 hours. At 22° C., the reaction was diluted with water (500 mL) and extracted with EtOAc (3×500 mL). The combined EtOAc layer was washed with water (3×100 mL), brine (100 mL), dried over Na2SO4, filtered and concentrated. The residue was chromatographed on silica gel 60, eluting with 0 to 50% EtOAc in hexane, to give the title product. 1H NMR (400 MHz, CDCl3) δ 8.13 (s, 1H); 7.16 (s, 1H); 6.02 (s, 1H); 5.05 (m, 1H); 4.49 (m, 3H); 4.00 (s, 3H); 3.91 (m, 2H); 3.78 (s, 3H); 2.67 (m, 1H); 2.37 (m, 1H); 1.47 (s, 3H); 1.44 (s, 9H) ppm. LRMS (ESI) m/z 525.0 [(M+H)+; calcd for C23H30BrN2O7: 298.0].

Provenance & Evidence