Reaction Steps
Hydrocinnamaldehyde (0.65 mL, 0.0049 mol) and compound 22 (2.00 g, 0.0049 mol) were mixed in anhydrous 1,2-dichloroethane (50 mL) and then treated with sodium triacetoxyborohydride (1.57 g, 0.0074 mol). The reaction mixture remains cloudy throughout the reaction. The mixture was stirred at room temperature under N2 atmosphere for 3 h. Reaction was monitored by TLC (20% EtOAc/hexanes; neutral Al2O3 Brockman activity II-III). After completion, the reaction mixture was quenched by adding saturated aqueous NaHCO3, and the product was extracted with EtOAc (3×50 mL). The combined EtOAc extract were dried (MgSO4), and the solvent was removed under reduced pressure to give crude product. The crude product was purified by flash chromatography (10% EtOAc/hexanes on neutral Al2O3 Brockman activity II-III) to afford 2.25 g (87%) of 23 as a white shiny solid. The sample used for X-ray analysis was recrystallized from a hexane and methylene chloride mixture: mp 136-138° C.; LCMS (ESI): m/z 523.7 (M+H)+; 1H NMR (CDCl3, 300 MHz) δ 7.79-7.82 [m, 2H], 7.68-7.71 [m, 2H], 7.18-7.32 [m, 8H], 6.76-6.81 [m, 1H], 4.81 [m, 1H], 3.85 [s, 3H], 3.31 [t, J=12 Hz, 1H], 2.94 [d, J=12 Hz, 1H], 2.80 [d, J=9 Hz, 1H], 2.67-2.73 [m, 3H], 2.34-2.53 [m, 4H], 2.25 [d, J=12 Hz, 1H], 1.78-1.94 [m, 3H], 1.51-1.62 [m, 2H], 1.49 [d, J=12 Hz, 1H], 1.31-1.37 [m, 1H], 1.26 [s, 3H]; 13C NMR (CDCl3, 300 MHz) δ 170.4, 160.9, 150.3, 144.5, 135.7, 134.0, 130.4, 130.3, 130.2, 127.6, 124.9, 123.5, 117.6, 112.6, 90.0, 63.6, 59.9, 57.2, 52.9, 49.5, 46.2, 38.6, 38.5, 37.3, 35.7, 35.6, 31.0, 28.3, 25.9. Anal. (C34H38N2O3) C, H, N.
