Cesium carbonate → (S)-4-[3-(tert-Butyldimethylsilanyloxy)-2-methylpropyl]-7-fluoro-4H-benzo[1,4]oxazin-3-one

Participants

Reaction Steps

7-Fluoro-4H-benzo[1,4]oxazin-3-one (111MF12) (2.52 g, 15.1 mmol), (S)-3-bromo-2-methylpropoxy-tert-butyldimethylsilane (4.03 g, 15.1 mmol) and Cs2CO3 (12.3 g, 38 mmol) were mixed according to GP7. CC (SiO2; Heptane/EtOAc 9:1) gave the title compound (111MF14) (3.79 g, 71%). 1H NMR (CDCl3) δ 7.12 (dd, J=5.2 Hz, J=8.8 Hz, 1H), 6.67-6.34 (m, 2H), 4.60 (q, J=14.8 Hz, J=25.4 Hz, 2H), 4.03 (dd, J=8.4 Hz, J=14.0 Hz, 1H), 3.82 (dd, J=5.6 Hz, J=14.0 Hz, 1H), 3.57 (dd, J=4.8 Hz, J=10.0 Hz, 1H), 3.45 (dd, J=7.0 Hz, J=9.8 Hz, 1H), 2.15-2.05 (m, 1H), 0.93-0.89 (m, 12H), 0.06 (s, 6H); 13C NMR (CDCl3) δ 164.1, 158.9 (d, J=243.7 Hz), 146.4 (d, J=11.6 Hz), 125.3 (d, J=3.0 Hz), 116.4 (d, J=9.6 Hz), 109.1 (d, J=22.7 Hz), 105.1 (d, J=25.8 Hz), 67.8, 66.0, 44.1, 34.5, 26.0, 18.4, 14.9, −5.3, −5.4.

Provenance & Evidence