Reaction Steps
A solution of 5.05 (8.90 g, 18 mmol) in DMF (60 mL) was treated with tert-butyldimethylsilyl chloride (6.8 g, 45.2 mmol) and imidazole (3.1 g, 45.2 mmol). After stirring for 8 h, the reaction was concentrated in vacuo. The residue was redissolved in CH2Cl2 then washed with H2O. The organic layer was dried over Na2SO4, decanted, and concentrated in vacuo. The residue was purified by silica gel chromatography (10% EtOAc/petroleum ether) to afford the title compound (10.5 g, 17.4 mmol, 96%). 1H NMR (600 MHz, CDCl3): δ ppm 7.38 (d, J=7.0 Hz, 2H, PhH), 7.33 (t, J=7.6 Hz, 2H, PhH), 7.30-7.26 (m, 3H, PhH, PMPH), 6.85 (d, J=8.2 Hz, 2H, PMPH), 4.92, 4.73 (ABq, J=11.1 Hz, 1H each, OCH2Ph), 4.68, 4.64 (ABq, J=11.4 Hz, 1H each, OCH2PMP), 4.34 (d, J=7.9 Hz, 1H, H-1), 4.04-3.98 (m, 1H, OCHHCH2SiMe3), 3.94 (br s, 1H, H-4), 3.89 (dd, J=10.3, 6.2 Hz, 1H, H-6), 3.82 (dd, J=10.4, 5.7 Hz, 1H, H-6), 3.80 (s, 3H, OMe), 3.64-3.54 (m, 2H, H-2, OCHHCH2SiMe3), 3.45 (dd, J=9.4, 3.2 Hz, 1H, H-3), 3.38 (t, J=6.0 Hz, 1H, H-5), 2.50 (br s, 1H, OH), 1.03 (t, J=8.5 Hz, 2H, OCH2CH2SiMe3), 0.90 (s, 9H, SiCMe3), 0.082, 0.078 (s, 3H each, SiMe2), 0.02 (s, 9H, SiMe3); 13C NMR (125 MHz, CDCl3): δ ppm 159.41, 138.99, 130.26, 129.56, 128.35, 128.14, 127.62, 113.93, 103.33, 80.55, 79.34, 75.23, 74.56, 72.18, 67.24, 66.75, 62.50, 55.33, 25.97, 18.59, 18.41, −1.32, −5.23, −5.28; HRMS calcd for C32H56NO7Si2 [M+NH4]+: 622.3595. found 622.3580.
