Reaction #7782

Reaction equation

methane boronic acid

[4-(1,3-benzoxazol-2-yl)-2-bromophenyl]acetonitrile

triphenylphosphine

potassium carbonate

→

[4-(1,3-benzoxazol-2-yl)-2-methylphenyl]acetonitrile

Solvents

DME H2O

Conditions

Workup

1. 1
   TemperatureThe mixture was cooled to rt
2. 2
   Otherthe two layers were separated
3. 3
   Extractionthe aqueous layer was extracted with EtOAc (3×)
4. 4
   Dryingdried over Na2SO4
5. 5
   Otherevaporated to dryness
6. 6
   Otherto give a brown solid
7. 7
   OtherPurification of the crude solid by flash chromatography on silica gel eluting with a gradient of EtOAc

Procedure

A mixture of methane boronic acid (57.6 mg, 0.96 mmol), [4-(1,3-benzoxazol-2-yl)-2-bromophenyl]acetonitrile (example 1) (200 mg, 0.64 mmol), dichlorobis(triphenylphosphine)palladium(II) (22.4 mg, 0.032 mmol), triphenylphosphine (17 mg, 0.064 mmol), and potassium carbonate (177 mg, 1.3 mmol) in degassed DME/H2O (5:1, 12 mL) was heated at 80° C. for 18 h. The mixture was cooled to rt, the two layers were separated and the aqueous layer was extracted with EtOAc (3×). The organics were combined, dried over Na2SO4 and evaporated to dryness to give a brown solid. Purification of the crude solid by flash chromatography on silica gel eluting with a gradient of EtOAc:hexanes (0 to 40 min: 0 to 25% EtOAc) afforded the desired [4-(1,3-benzoxazol-2-yl)-2-methylphenyl]acetonitrile as a yellow solid. 1H NMR (CDCl3, 300 MHz) δ 8.14 (s, 1H), 8.11 (d, 1H), 7.78 (m, 1H), 7.60 (m, 1H), 7.54 (d, 1H), 7.38 (m, 2H), 3.76 (s, 2H), 2.45 (s, 3H). MS (ESI) 249 (M+H)+.

Source