Reaction Steps
A mixture of compound 51 (7.00 g 24.50 mmol), allyl alcohol (80 mL) and p-tosic acid (742 mg, 3.90 mmol) was heated at reflux under a N2 atmosphere for 4 hOURS, at which time TLC (2% MeOH/CHCl3) indicated that reaction had gone to completion. Excess allyl alcohol was evaporated in vacuo to afford the crude compound (52), which was partitioned between NaHCO3 (50 mL) and EtOAc (50 mL). The organic layer was washed with water (3×50 mL), brine (3×50 mL) and then dried (MgSO4), and concentrated in vacuo. Purification by flash chromatography (CHCl3) yielded the product as an orange-brown solid (5.78 g, 72%). MP=73-75° C. 1H NMR (250 MHz, CDCl3) δ 7.70 (s, 1H), 7.16 (s, 1H), 6.00-5.84 (m, 1H), 5.36-5.21 (m, 2H), 4.94 (d, J=6.3 Hz), 4.62-4.59 (m, 2H), 4.13 (t, J=6.2 Hz, 2H), 3.97 (s, 3H), 2.67-2.56 (m, 3H), 2.20 (pent, J=6.7 Hz, 2H). 13C NMR 5173.1 (C12), 154.7 (Cquat.), 147.3 (Cquat.), 139.6 (Cquat.), 133.2 (Cquat.), 132.4 (C14), 118.7 (C15), 111.1 (C6), 109.9 (C3), 68.6 (C9), 65.6 (C13), 62.7 (C1), 56.7 (C8), 30.9 (C11), 24.6 (C10). IR (cm−1) 3329.4, 3100.0, 2972.1, 1734.5, 1647.9, 1577.4, 1508.1, 1281.5, 932.8, 884.0, 815.8, 758.2, 662.2. MS (M+ —OH) 308. Anal. Calcd for C16H19NO7: C, 55.38; H, 5.89; N, 4.31. Found: C, 52.41; H, 5.86; N, 4.67.
