反应详情

To a solution of (R)-3-tert-butoxycarbonylamino-4-(3′-chloro-biphenyl-4-yl)-2-hydroxy-butyric acid methyl ester (610 mg, 1.45 mmol) in CH3CN (20 mL) are added iodomethane (0.545 mL, 8.72 mmol) and silver oxide (1.35 g, 5.81 mmol). After being stirred at room temperature for 16 h, additional iodomethane (0.545 mL, 8.72 mmol) and silver oxide (1.35 g, 5.81 mmol) are added and stirred for 3 days. The reaction mixture is filtered through celite pad and the filtrate is washed with brine. The organic layer is dried over MgSO4 and concentrated. The residue is purified by flash column chromatography (silica gel, eluent; heptane/EtOAc=100:0 to 0:100) to give (R)-3-tert-butoxycarbonylamino-4-(3′-chloro-biphenyl-4-yl)-2-methoxy-butyric acid methyl ester (500 mg). HPLC retention time=1.20, 1.25 minutes (condition B): MS (m+1-Boc)=334. 1H-NMR (400 MHz, CDCl3) δ ppm 1.37, 1.41 (s, 9 H), 2.72-3.03 (m, 2 H), 3.43, 3.71 (s, 3H), 3.63-3.82 (m, 1 H), 4.27-4.41 (m, 1 H), 4.68-5.04 (m, 1 H), 7.28-7.40 (m, 4 H), 7.41-7.61 (m, 4 H).

1. stirringstirred for 3 days
2. filtrationThe reaction mixture is filtered through celite pad
3. washthe filtrate is washed with brine
4. dry with materialThe organic layer is dried over MgSO4
5. concentrationconcentrated
6. customThe residue is purified by flash column chromatography (silica gel, eluent; heptane/EtOAc=100:0 to 0:100)