Cesium carbonate → (S)-4-[3-(tert-Butyldimethylsilanyloxy)-2-methylpropyl]-6-methoxy-4H-benzo[1,4]oxazin-3-one

Participants

Reaction Steps

6-Methoxy-4H-benzo[1,4]oxazin-3-one (111MF24) (2.7 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) to give the title compound (111MF32) (4.03 g, 80%). 1H NMR (CDCl3) δ 6.89 (d, J=8.8 Hz, 1H), 6.71 (d, J=2.8 Hz, 1H), 6.50 (dd, J=2.8 Hz, J=8.6 Hz, 1H), 4.53 (q, J=14.8 Hz, J=29.2 Hz, 2H), 3.98 (dd, J=8.8 Hz, J=14.0 Hz, 1H), 3.85 (dd, J=5.8 Hz, J=14.2 Hz, 1H), 3.77 (s, 3H), 3.57 (dd, J=9.2 Hz, J=10.0 Hz, 1H), 3.47 (dd, J=7.2 Hz, J=10.0 Hz, 1H), 2.20-2.12 (m, 1H), 0.91 (s, 12H), 0.05 (d, J=1.2 Hz, 6H); 13C NMR (CDCl3) δ 165.3, 155.6, 139.7, 129.8, 117.2, 107.4, 103.3, 68.0, 66.2, 55.9, 43.9, 34.3, 26.1, 18.5, 14.7, −5.3, −5.4.

Provenance & Evidence