A solution of osmium tetroxide (50 mg, 0.2 mmol) in tert-butanol (8 mL) was added to a solution of 4-methylmorpholine N-oxide monohydrate (1.2 g, 9.1 mmol) in 100 mL (1:1) acetone/water solution and the mixture was stirred for 10 min at room temperature. After this time, 30 (3.1 g, 9.0 mmol) was added in 50 mL (1:1) acetone/water solution. The reaction mixture was stirred at room temperature overnight, then NaHSO3 (0.5 g) was added and the stirring was continued for 15 min. The acetone was evaporated and the pH was adjusted to 5.5 by the addition of 2N HCl then the mixture was extracted with ethyl acetate. The organic fraction was isolated, dried with sodium sulfate, and filtered through silica gel. Compound 31 (2.1 g, 62%) was isolated as a white solid after removing the solvent and drying under vacuum. 1H NMR (300 MHz, DMSO-d6) δ 1.48 (m, 2H), 1.50 (m, 2H), 2.46 (m, 2H), 3.00 (m, 2H), 3.43 (m, 2H), 3.80 (m, 2H), 3.93 (t, 1H), 4.66 (d, 1H), 4.99 (s, 2H), 6.82 (d, 2H), 7.07 (d, 2H), 7.26 (s, 1H), 7.33 (s, 5H).
