反応 #78002

反応方程式

difluoroketone

boron trifluoride etherate

Toluene

difluoroketone

→

1,2-dihydronaphthalene

収率 85.0%

溶媒

THF

反応条件

後処理

1. 1
   その他can range from 0° C. to 90° C
2. 2
   その他the reaction
3. 3
   workup.ADDITIONentire charge of the fluorinating reagent
4. 4
   その他the reaction
5. 5
   その他The product obtained
6. 6
   その他yield
7. 7
   その他in producing a high yield of the desired isomer
8. 8
   その他was used as solvent at 60° C.

実験手順

The reaction temperature can range from 0° C. to 90° C. In carrying out the reaction, the difluoroketone can be mixed with the entire charge of the fluorinating reagent or the reagent can be added dropwise to a solution of the difluoroketone. Lewis acid catalysts such as boron trifluoride etherate (BF3.Et2O) or HF can be used to accelerate the reaction. The product obtained is usually a mixture of the desired 1,1,2,2-tetrafluoro compound and the corresponding 1,1,2,4-tetrafluoro isomer. We have found that both the yield and the isomer ratio are highly dependent on the solvent used. Toluene is unexpectedly superior to other organic solvents in producing a high yield of the desired isomer. For example, when THF was used as solvent at 60° C., a 65% yield of 1,1,2,2-tetrafluoro-6-trans-4-propylcyclohexyl)-1,2-dihydronaphthalene was obtained (1,1,2,2-tetrafluoro/1,1,2,4-tetrafluoro=51/49), while when toluene was used as solvent at the same temperature, an 85% yield was obtained (1,1,2,2-tetrafluoro/1,1,2,4-tetrafluoro=90/10) under the same reaction conditions.

出典