give 401 mg (83%) of the title compound as a white powder. 1H NMR (DMSO-d6) δ 8.76 (bs, 3H), 7.96 (s, 1H), 4.93 (d, J = 16 Hz, 1H), 4.80 (d, J = 16 Hz, 1H), 4.28 (m, 1H), 3.18 (m, 2H), 2.61 (m, 1H), 2.30 (m, 1H), 1.93 (m, 2H), 1.70 (m, 1H); MS (ESI+) for C8H13ClN2O2m/z 205.0 (M + H)+.

tert-Butyl ((1S)-3-Bromo-2-oxo-1-{[(3S)-2-oxopyrrolidin-3-yl]methyl}propyl)carbamate (11)
A solution of tert-butyl ((1S)-3-chloro-2-oxo-1-{[(3S)-2-oxopyrrolidin-3-yl]methyl}propyl)carbamate (1.26 g, 4.3 mmol) in dichloromethan