Reaction Steps
A round bottom flask containing 48b (1.11 g, 4.17 mmol) in dry ether (27 mL) was immersed in a 25° C. water bath. n-BuLi (1.5 M in THF, 3.33 mL, 5.00 mmol) was added via syringe pump over one hour, generating a brown solution. Following addition of base, the reaction mixture was stirred at 25° C. for an additional 30 minutes and then cooled to −78° C. TMSCl (1.11 mL, 8.76 mmol) was added rapidly via syringe and the solution was subsequently warmed to room temperature. The reaction was diluted with ether, filtered, and concentrated in vacuo. Crude product was purified by flash column chromatography (20:1 hexanes-ethyl acetate followed by a second column 40:1 to 26:1 hexanes—ethyl acetate) to yield 49b as an orange solid in 78% yield (1.09 g, 3.24 mmol). 1H NMR (400 MHz, CDCl3): δ 7.57-7.60 (dd, 1H, J=8.4, 5.2 Hz), 7.19-7.22 (dd, 1H, J=9.6, 2.4 Hz), 7.00-7.04 (m, 2H), 6.78 (s, 1H), 4.01 (s, 3H), 3.97 (s, 1H), 2.61 (s, 3H), 2.49 (s, 3H), −0.15 (s, 9H); 13C NMR (150 MHz, CDCl3): δ 159.7 (d, J=289.5 Hz), 152.2 (d, J=10.1 Hz), 142.1, 141.2, 131.17, 129.4, 129.0, 122.7, 121.9, 121.7, 117.2 (d, J=10.5 Hz), 111.7 (d, J=27.9 Hz), 111.6 (d, J=29.7 Hz), 107.0, 38.2, 31.0, 21.8, 20.1, −2.2; 19F NMR (CD3CD, 376 MHz): δ −118.6 (m) FTIR: cm−1 2952, 1583, 1445, 1357, 1248, 1198, 1037, 838. EI-HRMS: Calcd. for C21H24FNSi+ [M]+: 337.1662. found 337.1664.
