A suspension of 3-(2-(4-(1H-benzo[d]imidazole-2-carbonyl)phenoxy)pyridin-3-yl)cyclopent-2-enone (2125 mg, 5.37 mmol) and cerium (iii) chloride (1325 mg, 5.37 mmol) in tetrahydrofuran (300 mL) and methanol (30.0 mL) was cooled to 0° C. under nitrogen. Sodium borohydrate (813 mg, 21.50 mmol) was added in 4 lots over 20 min. The reaction was warmed to 23° C. over 2 h. After a total reaction time of 4 h, the reaction was quenched with saturated ammonium chloride solution (10 ml, slowly—effervescence). The solution was diluted with EtOAc (500 mL) and washed with saturated ammonium chloride solution (100 mL) and brine (100 mL), dried over MgSO4, concentrated in vacuo and purified by silica gel chromatography (eluant: 1-8% methanol/dichloromethane), affording the product as a yellow film.
