Reaction Steps
To a round bottom flask were added tert-butyl((3S,7R,8R,9S)-7-(4-methoxybenzyl)-9-methyl-2-oxo-8-((triisopropylsilyl)oxy)oxonan-3-yl)(methoxymethyl)carbamate (1.61 g, 2.65 mmol), THF (26.5 ml) and TBAF (1.0 M, 5.30 ml, 5.30 mmol) at room temperature and an exotherm noted. The reaction was stirred at room temperature until thin layer chromatography (TLC) showed complete consumption of starting material. After approximately 2 h, the reaction was quenched by the addition of NaHCO3 and extracted with EtOAc (3×). The combined organic extracts were washed with brine, dried over MgSO4, concentrated, and purified by column chromatography on SiO2 (0→10%, hold, 10→20%, hold, 20→50% hold EtOAc/hexanes gradient) to furnish the title product as a colorless oil (703 mg, 59%): IR (neat) 3479, 2976, 2936, 1744, 1700, 1512, 1368, 1297, 1246, 1175 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.15-7.06 (m, 2H), 6.87-6.79 (m, 2H), 4.96-4.87 (m, 1H), 4.85-4.73 (m, 2H), 4.61-4.49 (m, 1H), 4.23-4.18 (m, 1H), 3.79 (s, 3H), 3.51 (td, J=8.8, 5.8 Hz, 1H), 3.32 (d, J=12.9 Hz, 3H), 3.01 (dd, J=13.6, 4.9 Hz, 1H), 2.44 (dd, J=16.2, 7.3 Hz, 1H), 2.07 (d, J=16.5 Hz, 1H), 1.69 (s, 2H), 1.63-1.49 (m, 3H), 1.44 (d, J=5.9 Hz, 9H), 1.40 (d, J=6.3 Hz, 3H), 0.94 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 173.45, 158.00, 129.72, 113.97, 76.28, 55.25, 37.08, 28.24, 27.29, 19.43, 18.18 (Note: Peaks missing, likely due to rotamers); HRMS-ESI (m/z) ([M]+) calcd for C24H37NO7, 451.2558; found, 451.257.
