To a solution of 3-(benzyloxycarbonylamino-methyl)-pyrrolidine-1,3-dicarboxylic acid 1-tert-butyl ester (2200.00 mg; 5.81 mmol; 1.00 eq.) in DCE (40.0 ml), bis(2-oxo-1,3-oxazolidin-3-yl)phosphinic chloride (1627.95 mg; 6.40 mmol; 1.10 eq.) was added. After stirring for 15 mins. DIEA (1.25 ml; 6.98 mmol; 1.20 eq.) and phenylamine (595.55 mg; 6.40 mmol; 1.10 eq) were added. The reaction mixture was stirred overnight at RT. DCM (100 ml) was added. The solution was washed with brine, dried and concentrated to give the crude product, which was subjected for biotage for purification (20-50% EtOAc in hexane) to afford the title compound (1800 mg, 68.3%).
