Reaction Steps
To a solution of a mixture of syn- and anti- isomers of 2-(4-methoxyphenyl)-1-phenyl-1-ethanone-O-methyl oxime (10, 1.65 g, 6.46 mmol) in THF (40 ml, freshly distilled from sodium benzophenone ketyl) under nitrogen was added borane-tetrahydrofuran solution (21.2 ml, 21.2 nmmol, 1.0 M solution, Aldrich) at room temperature. The resulting pale yellow solution was refluxed overnight, and cooled in an ice water bath. Water (50 ml) was carefully added to quench, followed by 20% NaOH (50 ml). The resulting colorless bi-phasic mixture was refluxed with vigorous magnetic stirring overnight, and allowed to cool to room temperature. Hexanes (40 ml) were added, and the layers separated. The aqueous portion was extracted with hexanes (1×40 ml). The combined organic portions were dried over potassium carbonate, and concentrated in vacuo to afford a colorless, slightly cloudy syrup. This syrup was purified by column chromatography on neutral alumina (I, 15 g) using an elution gradient of chloroform to 10% methanol/chloroform. The amine 15 was isolated as 1.263 g of a clear, colorless syrup (86% yield): Rf 0.20 (5% methanol/chloroform); IR (CDCl3) 3376 (w), 3316 (w), 3068 (w), 3031 (w), 3007 (w), 2965 (m), 2940 (m), 2910 (m), 2834 (m), 1614 (m), 1584 (m), 1514 (s), 1493 (m), 1466 (m), 1454. (m), 1441 (m), 1300 (m), 1245 (s), 1179 (m), 1106 (w), 1033 (m); 1H NMR (CDCl3) δ7.40-7.24 (m, 5H), 7.11 (d, J=8.6 Hz, 2H), 6.85 (d, 3=8.6 Hz, 2H), 4.18 (dd, J=8.6, 4.9 Hz, 1H), 3.81 (s, 3H), 2.98 (dd, J=13.5, 4.9 Hz, 1H), 2.79 (dd, J=13.5, 8.7), 1.49 (s, 2H). Low resolution mass spec. 228(M+1, 26), 211(49), 121(44), 107(69), 106(100), 79(100).
