Reaction Steps
To a solution of (2R,3S,4S)-2-(3-chlorophenyl)chromane-3,4-diol (9) (28 mg, 0.1 mmol) in CH2Cl2 (2 mL) was added manganese dioxide (44 mg, 0.5 mmol). The mixture was stirred at 23° C. for 24 h, filtered through a plug of Celite®, and concentrated under reduced pressure. The crude was purified by flash chromatography using 7% EtOAc/hexanes to afford 10 as a solid (16 mg, 59%). Analytical data for 9: 1H NMR (500 MHz, CDCl3) δ 7.93 (dd, J=7.9, 1.7 Hz, 1H), 7.62 (d, J=2.0 Hz, 1H), 7.58 (ddd, J=8.6, 7.2, 1.8 Hz, 1H), 7.48-7.45 (m, 1H), 7.42-7.38 (m, 2H), 7.14 (ddd, J=8.0, 7.2, 1.0 Hz, 1H), 7.07 (dd, J=8.4, 1.0 Hz, 1H), 5.12 (d, J=12.3 Hz, 1H), 4.57 (dd, J=12.3, 1.9 Hz, 1H), 3.70 (d, J=1.9 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 193.8, 161.5, 138.3, 137.1, 134.6, 129.9, 129.4, 127.6, 127.4, 125.8, 122.4, 118.4, 118.1, 83.0, 73.6; IR (film): 3461, 2921, 2851, 2361, 2341, 1695, 1608, 1579, 1466, 1300, 1229, 1138, 1104, 1009, 861, 764, 693, 419, 405 cm−1; LRMS (ESI): Mass calculated for [M+H]+ C15H12ClO3: 275.0; found 275.1.
