(R)-4-(4-((4′-chlorobiphenyl-2-yl)(hydroxy)methyl)piperidin-1-yl)benzoic acid (INTERMEDIATE 40, 2.15 g, 5.10 mmol), (R)-4-(4-((2-(tert-butyldimethylsilyloxy)ethyl)(ethyl)amino)-1-(phenylthio)butan-2-ylamino)-3-(trifluoromethylsulfonyl)benzenesulfonamide (INTERMEDIATE 65, 3.41 g, 5.10 mmol), DMAP (1.87 g, 15.29 mmol) and EDC (1.954 g, 10.19 mmol) were dissolved in DCM (17 ml). The reaction mixture was stirred at r.t. overnight, diluted with DCM (50 ml) and washed with NH4Cl solution (saturated, aq., 20 ml), saturated aq. NaHCO3 (20 ml) and brine (20 ml). The collected organic layer was dried over Na2SO4 and concentrated under reduced pressure. The concentrate was purified by column chromatography (ISCO, 12 g silica gel, eluted with 0→20% MeOH in EtOAc) to provide the title compound (3.41 g, yield: 62%).
