Reaction Steps
A solution of Compound 9 (2.20 g, 6.90 mmol) in THF (18 mL, 0.38M) was treated with 9-BBN (8.62 mmol, 1.25 equiv) in THF (17.25 mL, 0.5M) and the mixture was allowed to stir at 25° C. under N2 for 10 hours. The resulting mixture was treated successively with 4.15 mL of EtOH, 1.5 mL of 20 percent aqueous NaOH, and 1.65 mL of 50 percent aqueous H2O2. The reaction solution was warmed at 50° C. for one hour, recooled to 25° C., and partitioned between EtOAc (200 mL) and H2O (200 mL). The EtOAc layer was dried (Na2SO4) and concentrated under reduced pressure. Chromatography (SiO2, 5×15 cm, 10-25 percent EtOAc-hexane gradient elution) afforded the major isomer Compound 10 (1.29 g, 55.5 percent; Rf =0.32, 20 percent EtOAc-hexane) and Compound 11 (1S*,2R*,4S*,5R*,6S*-5-benzoyl-2-hydroxy-5-nitro-6-phenyl-bicyclo[[2.2.1]heptane, 400 mg, 17.2 percent; Rf =0.26, 20 percent EtOAc-hexane) as white solids cleanly separated from one another in a 3.2:1 ratio (1.69 g total, 2.32 g theoretical, 73 percent). For Compound 10: mp 168°-169° C. (EtOAc-hexane, colorless needles); 1H NMR (CDCl3, 250 MHz) δ7.38 (d, 2H, J=8.2 Hz), 7.31-6.94 (m, 8H), 4.33 (d, 1H, J=2.4 Hz, C5-H), 3.85 (d, 1H, J=6.8, C2-H), 3.29 (s, 1H, C1-H), 2.63 (d, J=11.3 Hz, C7-H syn to ketone), 2.46 (d, 1H, J=4.3 Hz, C4-H), 2.26-2.16 (m, 2H), 1.67-1.60 (m, 2H); 13C NMR (CDCl3, 50 MHz) δ189.9, 138.8, 133.7, 133.0, 128.9, 128.5, 128.3, 127.8, 127.4, 105.0, 69.3, 55.5, 55.4, 44.6, 42.1, 35.7; IR (neat) vmax 3331, 2968, 2900, 1689, 1538, 1444, 1353, 1234, 1096, 1063 cm-1 ; FABHRMS (NBA-NaI) m/e 360.1230 (C20H19NO4+Na+ requires 360.1212). Anal. Calcd for C20H19NO4 : C, 71.20; H, 5.68; N, 4.15. Found: C, 71.13; H, 5.89; N, 4.10. For Compound 11: 1H NMR (CDCl3, 250 MHz) δ7.34 (d, 2H, J=8.0 Hz), 7.25-6.90 (m, 8H), 4.18 (m, 2H), 3.25 (m, 1H), 2.62 (d, 1H, J=11.2 Hz), 2.26 (s, 1H), 2.12 (d, 1H, J=11.4 Hz), 1.80-1.62 (m, 2H), 1.45 (m, 1H); FABHRMS (NBA-CsI) m/e 470.0368 (C2H19NO4 +Cs+ requires 470.0368).
