“…Data for the dimethylimidazolidinone S1: state: yellow oil; 1 H NMR (600 MHz, CDCl 3 , 299 K): δ = 6.01 (dd, J = 1.8, 1.8 Hz, 2H), 3.88 (dd, J = 1.8, 1.8 Hz, 2H), 3.14 (sep, J = 1.8 Hz, 2H), 2.71 (s, 6H), 1.62 (ddd, J = 9.6, 1.8, 1.8 Hz, 1H), 1.22 (d, J = 9.6 Hz, 1H) ppm; 13 (10). 9 Diacetylimidazolidinone 1 (360 mg, 1.54 mmol) was dissolved in a mixture of acetone/water (15 mL, 4:1) at 25 °C. N-Methylmorpholine N-oxide (4.8 M in H 2 O, 0.35 mL, 1.69 mmol) was added to this solution, followed by (after 5 min) an addition of a commercial solution of OsO 4 (0.02 mL, 2 wt % in water).…”