1,2-Dibromo-1,1,2,2-tetrachloroethane → 2-Bromo-5-cyclopropyl-3-fluorobenzoic acid

Beteiligte Stoffe

Reaktionsschritte

To a solution of TMDA (1.3 ml, 8.61 mmol) in dry THF (9 mL) under inert atmosphere at −65° C., a 1.4M solution of sec-BuLi (8 ml, 11.20 mmol) was added dropwise. Then a solution of 3-cyclopropyl-5-fluorobenzoic acid (0.69 g, 3.83 mmol) in dry THF (3 mL) was added dropwise and stirred for 1 h. Then a solution of 1,2-dibromotetrachloroethane (5 g, 15.48 mmol) in dry THF (11 mL) was added dropwise for 1 h and stirred for additional 20 min. A white suspension was obtained. The cooling bath was removed and at −20° C. water (30 mL) and diethyl ether (30 mL) were added. The organic layer was separated and the aqueous phase was acidified (until pH: 1) using a 2N aqueous solution of HCl (13 mL needed) and extracted with diethyl ether. The organic phase was washed with water and brine, dried, filtered and concentrated in vacuo to afford a mixture 1:1 of the expected compound and starting material (38% yield), which was used without further purification

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