Diisopropylethylamine → (2S,5S)-2-(2-(6-bromonaphthalen-2-yl)-2-oxoethyl) 1-tert-butyl 5-methylpyrrolidine-1,2-dicarboxylate

Participants

Reaction Steps

DIPEA (0.823 mL, 4.71 mmol) was added to a stirred slurry of 2-bromo-1-(6-bromonaphthalen-2-yl)ethanone (Intermediate 118) (1.03 g, 3.14 mmol) and (2S,5S)-1-(tert-butoxycarbonyl)-5-methylpyrrolidine-2-carboxylic acid (0.720 g, 3.14 mmol) in acetonitrile (50 mL) and the reaction was stirred at rt overnight. The reaction was concentrated to dryness and purified by BIOTAGE® Horizon (40 g SiO2, 10-20% EtOAc/hexanes) to yield (2S,5S)-2-(2-(6-bromonaphthalen-2-yl)-2-oxoethyl) 1-tert-butyl 5-methylpyrrolidine-1,2-dicarboxylate (1.09 g) as a yellow solidified foam. LC-MS retention time 4.413 min; m/z 476, 478.20 (1:1) (MH+). LC data was recorded on a Shimadzu LC-10AS liquid chromatograph equipped with a PHENOMENEX® Luna 3u C18 2.0×50 mm column using a SPD-10AV UV-Vis detector at a detector wave length of 220 nM. The elution conditions employed a flow rate of 1 mL/min, a gradient of 100% Solvent A/0% Solvent B to 0% Solvent A/100% Solvent B, a gradient time of 4 min, a hold time of 1 min, and an analysis time of 5 min where Solvent A was 10% MeOH/90% H2O/0.1% trifluoroacetic acid and Solvent B was 10% H2O/90% MeOH/0.1% trifluoroacetic acid. MS data was determined using a MICROMASS® Platform for LC in electrospray mode. 1H NMR (400 MHz, MeOD) δ ppm 8.57 (br. s., 1H), 8.14 (d, J=1.5 Hz, 1H), 8.01 (d, J=8.5 Hz, 1H), 7.96 (d, J=8.8 Hz, 1H), 7.91 (d, J=8.8 Hz, 1H), 7.68 (dd, J=8.8, 1.8 Hz, 1H), 5.62-5.70 (m, 1H), 5.47-5.60 (m, 1H), 4.46 (t, J=7.3 Hz, 1H), 3.92-4.06 (m, 1H), 2.26-2.37 (m, 2H), 2.05-2.19 (m, 1H), 1.67-1.82 (m, 1H), 1.46 (d, J=6.8 Hz, 9H), 1.30 (d, J=6.5 Hz, 3H).

Provenance & Evidence