Reaction Steps
A solution of 27 (160 mg, 0.31 mmol) in anhydrous DMF (5 mL) under Ar was treated with NaH (19 mg, 0.47 mmol, 1.5 equiv, 60% oil dispersion) and the reaction mixture was stirred for 30 min at 0° C. Allyl bromide (194 mg, 139 μL, 1.55 mmol, 5 equiv) was added dropwise over 5 min and the solution was allowed to warm to 25° C. and stirred for 2 h. Saturated aqueous NaHCO3 (10 mL) was added and the aqueous phase was extracted with EtOAc (4×10 mL), dried (Na2SO4) and concentrated. Chromatography (SiO2, 2×15 cm, 10% EtOAc-hexane) afforded 28 (155 mg, 168 mg theoretical, 92%) as a clear oil which crystallized under vacuum: 1H NMR (CDCl3, 400 MHz) δ8.60 (s, 1H), 8.38 (d, 1H, J=8.6 Hz), 7.63 (d, 1H, J=8.4 Hz), 7.47-7.34 (m, 5H), 6.90 and 6.79 (two s, 1H), 5.94-5.84 (m, 1H), 5.27 and 5.22 (two d, 2H, J=12.3 Hz), 5.00 (m, 2H), 4.50 (dd, 1H, J=5.3, 14.4 Hz), 3.81 (dd, J=7.0, 14.4 Hz), 1.57 and 1.29 (two s, 9H); 13C NMR (CDCl3, 100 MHz) δ154.8, 144.9, 138.7, 135.7, 134.8, 133.2, 128.8, 128.3, 127.3, 126.9, 126.8, 124.2, 118.8, 118.4, 117.2, 112.2, 110.7, 80.8, 70.7, 53.3, 52.0, 28.4; IR (film) vmax 2977, 2228, 1703, 1593, 1503, 1410, 1368, 1324, 1250, 1223, 1150, 1108, 931, 830, 735, 696 cm-1 ; FABHRMS (NBA-CsI) m/z 672.9948 (M+ +Cs, C26H25IN2O3, requires 672.9964).
