反应详情

温度

-70 °C

A solution of 6.41 g (49.7 mmol) dichloroacetic acid in 20 ml THF is added dropwise at -70° C. within 30 minutes to a solution of lithium diisopropylamide under a nitrogen atmosphere prepared at 0° C. in 150 ml tetrahydrofuran from 11.2 g (110 mmol) diisopropylamine and 66.0 ml (105 mmol) butyllithium (1.6 M in hexane). It was allowed to stir for a further 30 minutes at -70° C. and the clear yellow solution was admixed with 15.0 g (50.0 mmol) 1,10 dibromodecane dissolved in 30 ml THF and the temperature was kept for 6 hours between -50 and -35° C. The concentration precipitate that first formed dissolved again in this process. For the processing 200 ml 3 N HCl was added and it was extracted with 200 ml ethyl acetate. The organic phase was washed with 3 N HCl and saturated NaCl solution and the aqueous phase was again extracted with 200 ml ethyl acetate. The combined organic phases were dried over sodium sulfate and the solvent was removed by distillation. Flash chromatography of the residue on silica gel (mobile solvent: petroleum ether/ethyl acetate 4:1, 1% glacial acetic acid) yielded 8.3 g (48%) 1, melting point 49-51° C. (isohexane).

1. waitthe temperature was kept for 6 hours between -50 and -35° C
2. customThe concentration precipitate that first formed
3. dissolutiondissolved again in this process
4. extractionit was extracted with 200 ml ethyl acetate
5. washThe organic phase was washed with 3 N HCl and saturated NaCl solution
6. extractionthe aqueous phase was again extracted with 200 ml ethyl acetate
7. dry with materialThe combined organic phases were dried over sodium sulfate
8. customthe solvent was removed by distillation