Methyl iodide → (2S,4S)-1-tert-butyl 2-methyl 4-(methoxymethyl)pyrrolidine-1,2-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of (2S,4S)-1-tert-butyl 2-methyl 4-(hydroxymethyl)pyrrolidine-1,2-dicarboxylate (2.57 g, 9.9 mmol) in CH2Cl2 (50 mL) was added AgOTf (4.07 g, 15.8 mmol) and 2,6-di-tert-butylpyridine (4.4 mL, 19.8 mmol). The reaction mixture was cooled to 0° C. (external temperature, ice bath) and MeI (0.98 mL, 15.8 mmol) was slowly added. The resulting slurry was stirred at 0° C. for 1.5 h and at room temperature for 1.5 h. The slurry was diluted with CH2Cl2 and filtered through celite. The filtrate was concentrated to dryness, dissolved in Et2O, and washed with HCl (1N) and brine. The aqueous layers were backextracted with Et2O and the combined organic layers were dried over Na2SO4 and concentrated. The crude oil was purified by silica gel chromatography (10% to 75% to 100% EtOAc/Hexanes) to provide (2S,4S)-1-tert-butyl 2-methyl 4-(methoxymethyl)pyrrolidine-1,2-dicarboxylate (2.11 g, 78%). 1H-NMR: 400 MHz, (CDCl3) δ: (mixture of rotamers, major reported) 4.20 (t, 1H), 3.71 (s, 3H), 3.67 (m, 1H), 3.34 (m, 2H), 3.30 (s, 3H), 3.16 (t, 1H), 2.43 (m, 2H), 1.74 (m, 1H), 1.38 (s, 9H).

Provenance & Evidence