反应详情

Step (i) n-Butyllithium (2.5M in hexane, 10.5 mL, 1.1 eq.) was added dropwise over 15 min to a solution of diisopropylamine (4.0 mL, 1.2 eq.) in THF (25 mL) at 0° C. After stirring for 15 min, the LDA solution was added dropwise over 40 min to a solution of 2,4,5-trifluorobromobenzene (5.0 g, 24 mmol) in THF (50 mL) at −78° C. The solution was stirred for 10 min and then transferred to a slurry of dry ice (50 g) in diethylether (65 mL). The reaction was allowed to warm to rt and treated with 1M HCl. The phases were separated and the organic layer extracted with 0.5M NaOH. The basic extracts were acidified to pH 1 with 6M HCl and extracted with diethylether. The combined organic phases were dried over sodium sulfate and evaporated to yield 3-bromo-2,5,6-trifluorobenzoic acid as a white solid (3.2 g, 52%). Step (ii)

1. stirringThe solution was stirred for 10 min
2. customThe phases were separated
3. extractionthe organic layer extracted with 0.5M NaOH
4. extractionextracted with diethylether
5. dry with materialThe combined organic phases were dried over sodium sulfate
6. customevaporated