Reaction Steps
10% cadmium-lead couple (109 mg, 0.875 mmol) was added to a stirred solution of the Troc-protected carbinolamine 13 (93 mg, 0.175 mmol) in THF (1 mL) and aqueous 1 N ammonium acetate (1 mL). After 45 minutes at room temperature TLC revealed complete reaction (70% EtOAc/Petroleum Ether). The mixture was diluted with EtOAc (30 mL), dried (MgSO4), filtered and evaporated in vacuo. The crude residue was purified by flash chromatography (70% EtOAc/Petroleum Ether) to provide the novel PBD (14, BSD-SJG, UP2023) as a white solid (27 mg, 46%): mp ° C.; 1H NMR (270 MHz, CDCl3+CD3OD) (11S,11aS isomer) δ 8.10 (d, 1H, J=1.46Hz), 7.65 (d, 1H, J=8.79 Hz), 6.86 (d, 1H, J=8.06 Hz), 5.14-5.10 (m, 2H), 4.66 (d, 1H, J=5.13 Hz), 4.34 (d, 1H, J=16.12 Hz), 4.23 (d, 1H, J=16.12 Hz), 3.80-3.71 (m, 1H), 3.34 (s, 3H), 3.03-2.86 (m, 1H), 2.65 (d, 1H, J=16.02 Hz); MS (EI), m/z (relative intensity) (N10-C11 imine form) 339 (M++1, 20), 338 (M+, 100), 337 (17), 323 (5), 311 (4), 310 (5), 257 (5), 230 (4), 229 (13), 211 (4), 203 (4), 202 (8), 184 (8), 183 (4), 103 (5), 82 (17), 81 (4), 80 (5), 76 (6), 75 (16), 74 (5), 55 (4), 53 (4); IR (NUJOL7) 3295 (br), 2923, 2853, 1716, 1615, 1506, 1457, 1377, 1317, 1278, 1238, 1169, 1118, 1063, 999, 895, 818, 751, 718 cm−1; exact mass calcd for C13H11N2OI m/e 337.9916, obsd m/e 337.9870.
