Triisopropyl borate → HCID 46739418、化合物

反応式

Br[C:2]1[CH:3]=[N:4][CH:5]=[C:6]([O:8][CH2:9][C:10]2[CH:15]=[CH:14][C:13]([O:16][CH3:17])=[CH:12][CH:11]=2)[CH:7]=1.[B:18]([O:27][CH:28]([CH3:30])[CH3:29])([O:23][CH:24]([CH3:26])[CH3:25])OC(C)C.C([Li])CCC>C1COCC1>[CH3:17][O:16][C:13]1[CH:14]=[CH:15][C:10]([CH2:9][O:8][C:6]2[CH:5]=[N:4][CH:3]=[C:2]([B:18]3[O:23][C:24]([CH3:25])([CH3:26])[C:28]([CH3:29])([CH3:30])[O:27]3)[CH:7]=2)=[CH:11][CH:12]=1

参加物

反応条件

温度: -78 °C

実験手順

To a solution of 3-bromo-5-(4-methoxy-benzyloxy)-pyridine (300 mg) in THF (10 mL) was added triisopropyl borate (0.28 mL) and the mixture cooled to −78° C. Then n-butyllithium (0.49 mL of a 2.5 M solution in hexanes) was added maintaining the temperature below −65° C. The reaction mixture was then allowed to warm to −20° C. over 1 h and then quenched with 2 M aqueous hydrochloric acid (2 mL). The mixture was allowed to warm to room temperature over 1 h and then diluted with water (25 mL), the pH was adjusted to 7 and then extracted into ethyl acetate (3×25 mL). The combined organics were washed with brine (20 mL), dried (MgSO4) and reduced in vacuo. A mixture of the crude product and pinacol (236 mg) in toluene (15 mL) was then heated at reflux for 4 h. The mixture was then reduced in vacuo, dissolved in ethyl acetate (30 mL) and washed with water (2×30 mL) and brine (30 mL). The combined organics were dried (MgSO4) and reduced in vacuo to give 3-(4-methoxy-benzyloxy)-5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-pyridine as an off-white solid (162 mg).