Example 1A Synthesis of (4S,5R)-4-hydroxy-5-(hydroxymethyl)dihydrofuran-2(3H)-one: 2-deoxy-D-ribose (10 g, 74.6 mmol) and water (60 mL) were added to a 500 mL round-bottomed flask, followed by slow dropwise addition of bromine (59.6 g, 373 mmol). The reaction mixture was stirred at room temperature for 5 days. After completion of the reaction, the mixture was diluted with water (300 mL) and extracted with tert-butyl methyl ether (3 x 200 mL). The aqueous layer was neutralized with silver carbonate to pH 6 and filtered to remove the resulting solid. The filtrate was concentrated under vacuum to give a residue. The residue was dissolved in ethyl acetate (200 mL) and dried by adding magnesium sulfate. After standing overnight, the solid was removed by filtration and the filtrate was concentrated to give (4S,5R)-4-hydroxy-5-(hydroxymethyl)dihydrofuran-2(3H)-one as an oil (7.72 g, 78%).1H NMR (400 MHz, CDCl3) δ 1.83 (t, J = 5.9 Hz, 1H), 2.13 (d, J = 4.3 Hz, 1H), 2.57 (dd, J = 4.3 Hz, 1H) 2.57 (dd, J = 18.1, 4.0 Hz, 1H), 3.00 (dd, J = 18.0, 7.2 Hz, 1H), 3.85 (m, 1H), 3.97 (m, 1H), 4.46 (q, J = 3.2 Hz, 1H), 4.65 (m, 1H).
