反应详情

tert-Butyl (2S)-2-(diazoacetyl)-1-pyrrolidinecarboxylate (16 g, 46 mmol) was dissolved in 50 mL anhydrous methanol. Silver benzoate (0.1 mL of a 1 g solution in 12 mL TEA) was added. After 14 at room temperature, Norit was added and the mixture was concentrated in vacuo. Purifcation on SiO2 (hexanes:EtOAc 6:1 then 4:1) provided the methyl ester as a clear oil (8.35 g, 34.3 mmol, 69% from Boc-proline): 1H NMR (400 MHz, CDCl3) δ 4.12 (bs, 1H), 3.65 (s, 3H), 3.34 (m, 2H), 2.85 (m, 1H), 2.29 (dd, J=9.6, 15.2 Hz, 1H), 2.1 (m, 1H), 1.8–1.6 (m, 3H), 1.44 (s, 9H) ppm. ESMS m/z 244 (MH)+, 144 (MH−C5H8O2)+.

1. concentrationthe mixture was concentrated in vacuo