m-Chloroperbenzoic acid → Benzyl 6-oxa-3-azabicyclo(3.1.0)hexane-3-carboxylate

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Reaction Steps

To a 1 L RB flask equipped with magnetic stirring bar was added benzyl 2,5-dihydro-1H-pyrrole-1-carboxylate (25 g, 123 mmol) and CH2Cl2 (246 ml). The resulting solution was cooled in an ice bath to 0° C., whereupon mCPBA (42.5 g, 246 mmol) was added in three portions over ˜15 min. The resulting slurry was naturally warmed up to rt over 2 days. LCMS indicates a complete reaction. The reaction was worked up as follows: the heterogeneous mixture was cooled to −15° C. for 1 hour, filtered to remove the solid which was rinsed with cold DCM. The resulting filtrate was washed with 1N aq. NaOH (4×100 mL), water (100 mL) and brine, then dried with anhydrous sodium sulfate. DCM phase was concentrated to benzyl 6-oxa-3-azabicyclo[3.1.0]hexane-3-carboxylate (24.5 g, 91% yield) as light yellow oil. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 7.31-7.44 (5 H, m), 5.08-5.21 (2 H, m), 3.90 (2 H, dd, J=19.70, 12.65 Hz), 3.65-3.77 (2 H, m), 3.42 (2 H, ddd, J=12.76, 6.16, 1.10 Hz); LCMS (Chromolith RP-18e 2.0×50 mm, 0.8 mL/min, Solvent A: 10% MeOH/water with 0.1% TFA, Solvent B: 90% MeOH/water with 0.1% TFA, gradient with 0-100% B over 4 minutes) retention time: 2.41 min; MS (ES+) m/z: 242.0 (M+Na+);

Provenance & Evidence