Reaction Steps
10% Cd/Pb couple (516 mg, 4.21 mmol, 25 eq) was added to a rapidly stirring mixture of 23 (234 mg, 0.17 mmol), THF (5 mL) and 1 N NH4OAc (5 mL). The reaction mixture was allowed to stir for 5 hours when TLC showed complete consumption of the starting material and formation of a small amount of side products. The solids were filtered and rinsed with H2O and a large amount of MeOH. Excess solvent was removed and the residue was diluted with H2O (35 mL) and CHCl3 (35 mL). The aqueous layer was extracted with CHCl3 (3×30 mL) and the organic extracts were combined, washed with brine (100 mL) and dried (MgSO4). Filtration and evaporation of solvent afforded the crude product which was purified by flash column chromatography (99.5:0.5 v/v CHCl3/MeOH then gradient to 96:4 v/v CHCl3/MeOH) to afford 24 as a yellow glass (44 mg, 33%): 1H NMR (400 MHz, CDCl3) 8.85 (dd, 2H, J=1.6, 4.2 Hz, Harom), 8.09 (d, 2H, J=7.6 Hz, Harom), 8.03 (d, 2H, J=9.0 Hz, Harom), 7.88 (d, 2H, J=3.9 Hz, H11), 7.82 (dd, 2H, J=1.8, 8.9 Hz, Harom), 7.24 (s, 2H, H3), 7.59 (s, 2H, Harom), 7.52 (s, 2H, H6), 7.48 (dd, 2H, J=4.3, 8.3 Hz, Harom), 6.88 (s, 2H, H9), 4.48-4.42 (m, 2H, H11a), 4.39-4.28 (m, 4H, OCH2CH2CH2O), 3.94 (s, 6H, OCH3×2), 3.76-3.63 (m, 2H, H1), 3.09-2.98 (m, 2H, H1), 2.46-2.43 (m, 2H, OCH2CH2CH2O).
