Reaction Steps
Following a general procedure (Lub et al. (1997) Liebigs Ann. Recueil, 2281-2288), 13 (845 mg, 3.60 mmol) and thioacetic acid (910 μL, 12.7 mmol) were dissolved in toluene (20 mL) and the solution was purged with argon for 15 min. Then AIBN (200 mg) was added and the mixture was heated to 90° C. Over a period of 23 h more AIBN (1.10 g) was added in several portions. Then aq NaHCO3 (10%, 50 mL) was added and the phases were separated. The aqueous phase was washed with ether and the combined organic phases were dried (Na2SO4). Purification by column chromatography (silica, ether/hexanes, 1:4) gave an orange oil, which solidified upon standing at −20° C. and was recrystallized from pentane to give 708 mg (63%) of colorless needles. mp 44° C. IR (neat): {tilde over (v)} 2951, 2850, 1692, 1620, 1518; 1H NMR δ 0.79 (s, 3H), 1.29 (s, 3H), 1.78-1.94 (m, 2H), 2.33 (s, 3H), 2.68 (t, 3J=7.3 Hz, 2H), 2.86 (t, 3J=7.3 Hz, 2H), 3.64 (d, 2J=11.0 Hz, 2H), 3.76 (d, 2J=11.0 Hz, 2H), 5.37 (s, 1H), 7.18, 7.42 (AA′BB′, 2×2H); 13C NMR (APT) δ 21.6 (−), 22.8 (−), 28.1 (+), 29.9 (+), 30.4 (−), 30.8 (+), 34.3 (+), 77.3 (+), 101.4 (−), 126.0 (−), 128.1 (−), 136.1 (+), 141.5 (+), 195.3 (+); GC-MS (EI) obsd 308, 307, 265, 232, 221, 204, 199, 180, 146, 133, 115, 91, 69, 43; Anal. Calcd for C17H24O3S: C, 66.20; H, 7.84; S, 10.40. Found: C, 66.19; H, 7.89; S, 10.54.
