Reaction Steps
Solid sodium tetraborohydride (NaBH4, 70 mg, 1.88 mmol) was added in one portion to a rapidly stirring solution of 178 (100 mg, 0.2 mmol) in a mixture of anhydrous EtOH (2 mL) and anhydrous THF (4 mL) and left to stir at room temperature for 9 h. The reaction mixture was diluted with water (10 mL) and stirred for 30 minutes with silica gel (2.0 g). The mixture was extracted with EtOAc (3×10 mL). The organic layers were washed with brine (10 mL) and dried over anhydrous MgSO4. Filtration and evaporation afforded the crude product (179), which was purified by flash column chromatography eluting with a 50:50 mixture of petroleum ether:EtOAc. Pure fractions were combined and evaporation of the solvent in vacuo afforded the product as a yellow glass (28 mg, 0.08 mmol, 38%). 1H NMR (270 MHz, CDCl3) δ7.89 (d, 1H, J=4.03 Hz, Imine CH), 7.53 (s, 1H, ArH), 7.39 (t, 1H, J=1.83 Hz, H3), 7.33 (d, 2H, J=8.97 Hz, methoxyphenyl ArH), 6.91 (d, 2H, J=8.98 Hz, methoxyphenyl ArH), 6.83 (s, 1H, ArH), 4.44-4.36 (m, 1H, H11a), 3.97 (s, 3H, OMe), 3.94 (s, 3H, OMe), 3.91-3.79 (m, 4H, H1+Suzuki ArOMe), 3.64-3.34 (m, 1H, H1); 13C NMR (67.8 MHz, CDCl3) δ162.7, 161.3, 159.2, 151.8, 147.8, 140.4, 126.3, 126.2, 126.0, 125.9, 123.2, 121.9 114.3, 114.1, 111.6, 109.8, 56.2, 56.1, 55.6, 35.6.
