To a stirred solution of 3-phenyl-1-(toluene-4-sulfonyl)-1H-indole-2-carboxylic acid ethyl ester (3.24 g, 7.72 mmol) in toluene (40 mL) at −78° C. and under a nitrogen atmosphere was added 1.0M DIBAL-H in toluene (23.2 mL, 23.2 mmol). The reaction mixture was stirred at −78° C. for 15 min then at −10° C. for 30 min. After re-cooling to −78° C., the reaction mixture was quenched with water (20 mL) then allowed to warm to RT. The mixture was partitioned between EtOAc and 1.0M HCl and the aqueous phase was extracted with additional EtOAc (×3). The combined organic fractions were washed with water, dried (Na2SO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, gradient 30-100% DCM in pentane) affording the title compound as a white foam (2.49 g, 85%). LCMS (Method C): RT 4.77 min [M+Na]+ 400.1
