5-Chloro-2-methylbenzoxazole → Benzoxazole

Participants

Reaction Conditions

Reaction Steps

To form 5-vinyl-2-methylbenzoxazole (4aa), the general procedure was followed using 5-chloro-2-methylbenzoxazole (3d) (167 mg, 1.01 mmol), vinyl MIDA boronate (2g) (218 mg, 1.19 mmol), SPhos (42 mg, 0.10 mmol) and Pd(OAc)2 (11 mg, 0.050 mmol). The reaction time and temperature were modified so that the reaction mixture was heated to 100° C. for 2 h. Benzoxazole 4aa was isolated as a pale golden liquid (152 mg, 96%). TLC (hexanes:EtOAc 3:1) Rf=0.46, visualized by UV (254 nm). 1H-NMR (500 MHz, CDCl3 w/TMS) δ 7.67 (s, 1H), 7.38 (d, J=8.0 Hz, 1H), 7.34 (d, J=8.0 Hz, 1H), 6.79 (dd, J=17.5, 11.0 Hz, 1H), 5.74 (d, J=17.5 Hz, 1H), 5.24 (d, J=11.0 Hz, 1H), 2.61 (s, 3H). 13C-NMR (125 MHz, CDCl3) δ 164.3, 150.6, 141.9, 136.5, 134.2, 122.9, 116.8, 113.4, 109.9, 14.5. HRMS (EI+) Calculated for C10H9NO (M)+: 159.0684, Found: 159.0685. IR (KBr, cm−1) 3087, 3006, 2984, 2928, 1623, 1622, 1578, 1477, 1433, 1381, 1335, 1262, 1179, 1114, 1040, 989, 918, 881, 840, 815.

Provenance & Evidence