Reaction Steps
A solution of 4b (165 mg, 0.64 mmol) in anhydrous THF (520 μL) was added dropwise to a solution of nBuLi (2.5 M in hexanes, 390 mL, 0.97 mmol) in anhydrous THF (420 μL) at room temperature. After 1 hour, the solution was cooled to −78° C. and methyl iodide (160 μL, 2.58 mmol) was added. The resulting solution was warmed to room temperature over 12 hours, and the reaction was quenched by the addition of saturated aqueous NH4Cl. Water (5 mL) was added and the solution was extracted with CH2Cl2 (3×10 mL). Combined organic fractions were dried (Na2SO4), filtered, and concentrated. The residue was purified via column chromatography (SiO2, 6:1 Hexane:EtOAc) to afford 5b as a yellow oil (166 mg, 95%): 1H NMR (CDCl3, 500 MHz) 6.66 (d, J=9.0 Hz, 1H), 6.60 (d, J=9.0 Hz, 1H), 5.02 (s, 2H), 5.00 (s, 2H), 3.80-3.77 (m, 2H), 3.49 (s, 3H), 3.47 (s, 3H), 2.14 (d, J=7.1 Hz, 3H), 1.73-1.69 (m, 2H), 0.94 (t, J=7.5 Hz, 3H); 13C NMR (CDCl3, 125 MHz) δ 148.5, 148.5, 147.3, 145.6, 126.7, 123.0, 112.8, 110.8, 110.4, 99.2, 57.7, 57.6, 21.2, 10.9, 10.0; IR (film) νmax 2957, 2924, 2853, 1738, 1597, 1487, 1468, 1391, 1335, 1231, 1157, 974, 798 cm−1; HRMS (ESI+) m/z: [M+H]+ calcd for C14H22O5, 271.1545; found, 271.1558.
