反应详情

To a solution of the product from Step D (21.5 g, 75.6 mmol) in DCM (400 mL) was added TEA (31.6 mL, 226.8 mmol) and benzyl chloroformate (14.5 mL, 95%, 98.3 mmol) at 0° C. under Ar. The mixture was stirred at rt for 3 h and quenched by the addition of aqueous NaHCO3 solution. The aqueous phase was extracted with DCM (3×) and the combined organic phases were dried over Na2SO4. Evaporation and purification by column chromatography (eluent: 20% EtOAc in hexanes to 30%) gave the product as a colorless gel. 1H-NMR (400 MHz, CDCl3): δ 1.43 (s, 9H), 1.89 (br. s., 2H), 2.13 (br. s., 2H), 2.99 (d, J=1.0 Hz, 1H), 3.22-3.57 (m, 2H), 3.59-3.83 (m, 4H), 3.99 (d, J=11.6 Hz, 1H), 4.23 (d, J=5.8 Hz, 1H), 4.85 (br. s., 1H), 5.12 (d, J=3.0 Hz, 2H), 7.28-7.42 (m, 5H). LC/MS: C22H30N2O6: m/z 441.2 (M+Na).

1. customquenched by the addition of aqueous NaHCO3 solution
2. extractionThe aqueous phase was extracted with DCM (3×)
3. dry with materialthe combined organic phases were dried over Na2SO4
4. customEvaporation and purification by column chromatography (eluent: 20% EtOAc in hexanes to 30%)