Reaction Steps
A mixture of alcohol α36 (62 mg, 0.21 mmol) and 2,6-lutidine (50 μL, 0.43 mmol) in CH2Cl2 (2 mL) was cooled to −78° C., and 63 μL (0.27 mmol) of TBSOTf was added. The stirred cold solution was warmed to 0° C. over 5 h. MeOH (40 μL, 1 mmol) was then added to quench the excess TBSOTf. The resulting mixture was concentrated via rotary evaporation, and the crude residue was purified by flash column chromatography (EtOAc/hexanes; 1:5) to afford 82 mg (95%) of α37 as a white solid. mp 89.0-90.0° C.; [α]20D=−30.5 (c=0.61, CH2Cl2); 1H NMR (CDCl3, 300 MHz) δ 7.93-7.97 (m, 2H), 7.55-7.70 (m, 3H), 7.09 (d, J=5.1 Hz, 1H), 3.70 (dd, J=8.4 Hz, 2.1 Hz, 1H), 3.67 (d, J=4.8 Hz, 1H), 3.37 (dd, J=7.2 Hz, 4.2 Hz, 1H), 2.60 (m, 1H), 2.49 (m, 1H), 1.26 (d, J=7.2 Hz, 3H), 0.90 (s, 9H), 0.74 (d, J=7.2 Hz, 3H), 0.10 (s, 3H), 0.09 (s, 3H); 13C NMR (CDCl3, 75 MHz) δ 146.0, 140.2, 136.1, 133.7, 129.3, 128.4, 74.5, 56.8, 48.7, 40.9, 36.9, 25.9, 18.4, 18.1, 9.7, −4.3, −4.4; Analytical. Calculated for C21H32O4S: C, 61.72; H, 7.89. Found: C, 61.39; H, 7.59.
