Reaktion #717035

Reaktionsgleichung

NaBH4

Toluene

2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde

cyclohexylamine

→

N-(2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)cyclohexanamine

Lösungsmittel

formic acid

Et2O

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeto form a clear solution
2. 2
   Temperaturto reflux
3. 3
   Sonstigethe toluene/water mixture collected till clear
4. 4
   Sonstigethe solution evaporated to 100 mL
5. 5
   workup.ADDITIONMeOH (200 mL) was then added to the reaction mixture
6. 6
   Sonstigequenched with water (5 mL)
7. 7
   SonstigeThe solution was evaporated to 100 mL and EtOAc (50 mL)
8. 8
   workup.ADDITIONwas added
9. 9
   TrocknenThe solution was dried with Na2SO4
10. 10
    Sonstigethe solvent removed by reduced pressure
11. 11
    Sonstigeyielding a white solid
12. 12
    workup.DISSOLUTIONdissolving half of the white solid
13. 13
    SonstigeThe remaining solid was collected
14. 14
    Sonstigedried under reduced pressure

Vorschrift

Toluene (250 mL) was added to 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde (5.0 g, 21.54 mmol) followed by cyclohexylamine (2.37 g, 23.89 mmol) and formic acid (˜1.0 mL of 88%) to form a clear solution. The mixture was allowed to reflux using a Dean-Stark trap and the toluene/water mixture collected till clear. Upon completion, the mixture was cooled to room temperature and the solution evaporated to 100 mL. MeOH (200 mL) was then added to the reaction mixture followed by NaBH4 (1.63 g, 43.08 mmol) portion wise. The mixture was stirred for 20 min and quenched with water (5 mL). The solution was evaporated to 100 mL and EtOAc (50 mL) was added. The solution was dried with Na2SO4 and the solvent removed by reduced pressure, yielding a white solid. Et2O (200 mL) was then added dissolving half of the white solid. The remaining solid was collected and dried under reduced pressure offering compound 7. Yield: 6.3 g, 46.4%. 1H NMR (CD2Cl2): δ 7.52-7.50 (d, 1H), 7.28-7.27 (m, 2H), 7.15-7.13 (d, 1H), 4.02 (s, 2H), 3.42 (s, 1H), 3.15-3.07 (m, 1H), 1.74-1.61 (m, 5H), 1.29 (s, 12H), 1.19-1.05 (m, 6H).

Quelle