Tetrahydrofuran → 3-Bromo-5-fluorobenzaldehyde

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

step 1—To a solution of iso-propylmagnesium chloride in THF (500 mL of a 2M solution in THF, 1.0 mol) and THF (200 mL) was added a solution of 3,5-dibromofluorobenzene (25; 200 g, 0.79 mol) in THF (100 mL) while maintaining the temperature at ca. 0 C. After rinsing with THF (3×20 mL) the mixture was aged for 2 h at ca. 0° C. and then warmed to ca. 20° C. and aged for 0.5 h. The reaction was sampled by HPLC and then cooled to ca. 0° C. DMF was added over 0.5 h while maintaining the temperature at ca. 0° C. The mixture was aged 1.5 h at ca. 0° C. and then warmed slowly to ca. 20° C. overnight. After sampling by HPLC, the mixture was diluted with heptane (200 mL) and then with a mixture of con HCl (120 mL) diluted to 360 mL with water. Con HCl (50 mL) was added to adjust the pH to <7. The organic phase was separated, washed with water (400 mL) and evaporated to dryness to afford 160.8 g (100.5%) of 28 as a yellow oil which solidified on standing.

Herkunft & Nachweise