Example 19
To a solution of 15 (408 g, 0.77 mol, 1.0 eq.) and methyl iodide (145 mL, 2.32 mol, 3.0 eq.) in THF (4 L) was added sodium hydride (60% dispersion in mineral oil, 62.2 g, 1.55 mol, 2.0 eq.) at 0° C. The resulting mixture was stirred at 0° C. overnight and then poured onto ice-water cooled saturated ammonium chloride (5 L) with vigorous stirring. The mixture was then extracted with EtOAc (3×500 mL) and the organic layers were dried, filtered, concentrated and purified by column chromatography with a gradient of 15-35% EtOAc in petroleum ether to afford product 16 (388 g, 93% yield) as a light yellow oil. 1H NMR (500 MHz, CDCl3) δ 8.09 (s, 1H), 4.95 (d, J=6.6 Hz, 1H), 4.41 (q, J=7.1 Hz, 2H), 3.56 (d, J=9.5 Hz, 1H), 2.98 (s, 3H), 2.27-2.06 (m, 4H), 1.83-1.70 (m, 2H), 1.41 (t, J=7.2 Hz, 3H), 1.29 (ddd, J=8.9, 6.8, 1.6 Hz, 3H), 1.01 (d, J=6.6 Hz, 3H), 0.96 (dt, J=8.0, 2.9 Hz, 15H), 0.92 (d, J=6.6 Hz, 3H), 0.90 (d, J=6.7 Hz, 3H). MS ESI m/z calcd for C25H46N5O4SSi [M+H]+ 540.30, found 540.30.
