Reaction Steps
A solution containing 180 mg (0.825 mmol) compound (2e) and 22.5 mg (0.123 mmol) benzophenone in 110 mL [1,3]-dioxolane was irradiated at 20° C. for 7 hours according to the general procedure. Column chromatography (silica gel 40 g, ethyl acetate in hexanes 40%) gave compound (3e) (193 mg. 80%) as a colorless solid, Rf=0.29, [α]25D 35.2°, c 1.2, CHCl3, IR (neat) 2360, 2342, 1779, 1721, 1272, 1118 cm−1; 1H-NMR (400 MHz, CDCl3) δ: 2.53 (d, 1H J=11.6 Hz), 2.62-2.73 (m, 2H), 3.83 (mc, 2H), 3.94 (mc, 2H), 4.37 (dd, 1H, J=5.1 Hz, J=12.3 Hz), 4.53 (dd, 1H, J=2.9 Hz, J=12.3 Hz), 4.74 (ddd, 1H, J=2.9 Hz, J=5.1 Hz, J=6.9 Hz), 4.88 (d, 1H, J=3.4 Hz), 7.37 (dd, 2H, J=7.7 Hz, J=7.9 Hz), 7.49 (dd, 1H, J=1.0 Hz, J=7.7 Hz), 7.92 (dd, 2H, J=1.0 Hz, J=7.9 Hz). 13C-NMR (100.6 MHz, CDCl3, Dept) δ: 29.77 (−), 40.06 (+), 65.37 (−), 65.50 (−), 65.99 (−), 77.56 (+), 103.14 (+), 128.51 (+), 129.31 (quat), 129.57 (+), 133.30 (+), 166.00 (quat) 175.62 (quat). C15H16O6; Exact Mass: 292.09; Mol. Wt.: 292.28; C, 61.64, H, 5.52, O, 32.84.
