To a solution of 2,6′-diformyl-4,2′,3′,4′-tetramethoxybiphenyl-3-yl methanesulfonate (170 mg, 0.40 mmol) in methanol (4 mL) was added sodium borohydride (45 mg, 1.20 mmol) and the solution was stirred at room temperature for 1 hour. Water (20 mL) and ethyl acetate (20 mL) were added to the reaction, the layers were separated and the aqueous layer was extracted with ethyl acetate (2×20 mL). The combined extracts were dried over Na2SO4 and filtered. The solvent was removed in vacuo and the residue was purified by flash chromatography over silica gel (25 g), eluting with hexane-ethyl acetate (1:2), followed by crystallisation (ethyl acetate), which yielded 2,6′-bis(hydroxymethyl)-4,2′,3′,4′-tetramethoxybiphenyl-3-yl methanesulfonate as a white solid (164 mg, 96%); m.p. 124-126° C.; High Resolution Mass Spectrometry Found: M+Na+ 451.1041 (C18H20O7Na requires 451.1039); NMR Spectrum δH (300 MHz, CDCl3) 7.08 (1H, d, J 8.4 Hz, 6-H), 7.01 (1H, d, J 8.4 Hz, 5-H), 4.64 (1H, d, J 12.0 Hz, 2-CHAOH), 4.26 (1H, d, J 12.0 Hz, 2-CHBOH), 4.18 (2H, dd, J 2.9, 11.8 Hz, 6′-CH2OH), 3.94 (3H, s, OCH3), 3.92 (3H, s, OCH3), 3.88 (3H, s, OCH3), 3.56 (3H, s, OCH3), 3.40 (3H, s, SCH3); NMR Spectrum δC (75 MHz, CDCl3) 50.2, 56.5, 56.9, 61.2, 61.5, 106.2, 116.8, 127.5, 130.0, 130.7, 131.0, 132.1, 139.8, 147.6, 151.1, 152.6, 154.0, 189.3, 190.5; νmax/cm−1 (thin film) 3219, 2947, 1607, 1484, 1410, 1363, 1328, 1278, 1161, 1111, 1006, 889; m/z (ES) 447 (MNa2H2O+, 100%); Rf (hexane-ethyl acetate 1:2) 0.18.
