Sodium hydride → diethyl 1-{(2R)-1-[(tert-butoxycarbonyl)amino]propan-2-yl}-1H-indole-2,6-dicarboxylate

Participants

Reaction Steps

A stirred suspension of 60% NaH (371 mg, 9.3 mmol) in DMF (10 mL) is cooled in an ice bath, and a solution of diethyl 1H-indole-2,6-dicarboxylate (Intermediate A, 2.6 g, 10.1 mmol) in DMF (10 mL) is added. The mixture is stirred for 20 min, then a solution of tert-butyl (5S)-5-methyl-1,2,3-oxathiazolidine-3-carboxylate 2,2-dioxide (2.0 g, 8.4 mmol) in DMF (10 mL) is added. The reaction mixture is stirred for 30 min at 0° C. and then warmed to room temperature and stirred for 48 h. The reaction is poured into ice water and the resultant solid is removed by filtration. The filtrate is acidified to pH 3 with 1N aqueous HCl and extracted with EtOAc. The combined extracts are washed with water, brine, dried (Na2SO4) and concentrated to afford the title compound (2.7 g, crude) as an oil.

Provenance & Evidence