反应详情

温度

-40 °C

A solution of diisopropyl amine (17.77 ml, 126 mmol) in 320 ml THF was cooled to −75° C. and brought under N2 atmosphere. A 1.6 M solution of BuLi in hexane (79 ml, 126 mmol) was added. When the LDA solution had cooled down again, 1-fluoro-4-bromobenzene was added. The reaction temperature was kept below −60° C. After 2.5 h ethyl difluoro acetate (15.60 g, 126 mmol) was added rapidly and after 15 minutes, the reaction mixture was warmed to −40° C. After 15 minutes the mixture was quenched by pouring it on ice-cold 1N HCl. The mixture was extracted with petroleum ether (B.p. 40-60° C.) and the extract was dried with MgSO4.H2O. Chromatography on silica gel with hexane/TBME 9/1->6/1 gave 22.1 g yellow liquid.

1. customwas kept below −60° C
2. customAfter 15 minutes the mixture was quenched
3. additionby pouring it on ice-cold 1N HCl
4. extractionThe mixture was extracted with petroleum ether (B.p. 40-60° C.)
5. dry with materialthe extract was dried with MgSO4.H2O