Reaction Steps
To the above mixture of crude product 15 and N-benzyl-N-(1-phenyl-ethyl)-benzamide in methanol (30 mL) and water (15 mL) was added lithium hydroxide (831 mg, 34.7 mmol). The resulting suspension was heated to reflux for 48 hours. After cooled downed, the mixture was concentrated to remove methanol. The water layer was taken up with CH2Cl2 (30 mL×3). The organic layer was dried and concentrated. The residue was purified by silica gel column using hexane and ethyl acetate (2:1) as eluent to give 1.406 g white solid, in 85% yield for two steps. 1H NMR (400 MHz, CDCl3): δ7.44 (d, J=8.52 Hz, 2H), 7.37-7.22 (m, 12H), 6.55 (brs, 1H), 4.43 (dd, J1=4.46 Hz, J2=11.32 Hz, 1H), 4.15 (q, J=6.87 Hz, 1H), 3.98 (d, J=13.68 Hz, 1H), 3.64 (d, J=13.68 Hz, 1H), 2.92 (dd, J1=11.34 Hz, J2=16.94 Hz, 1H), 2.41 (dd, J1=4.48 Hz, J2=16.96 Hz, 1H), 1.54 (s, 9H), 1.28 (d, J=6.88 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 174.39, 152.82, 141.25, 138.44, 137.70, 132.56, 129.22, 128.80, 128.62, 128.60, 128.19, 127.81, 127.53, 118.52, 80.86, 57.96, 57.82, 50.61, 36.29, 28.34, 15.68. mp 93-95° C. IR v (Diamond, cm−1): 3307, 1699, 1594, 1081, 698. MS (ESI) m/z found 475.6 (M+H)+.
