Reaction #2507817

Reaction equation

iodine

n-butyllithium

7-bromo-6-fluoro-3-propylchroman

→

6-fluoro-7-iodo-3-propylchroman

Solvents

THF

hexane

THF

Conditions

Workup

1. 1
   workup.ADDITIONare added
2. 2
   Otherthe cooling is removed
3. 3
   workup.ADDITIONThe batch is diluted with MTB ether
4. 4
   Washwashed with water and with sat. sodium hydrogensulfite soln
5. 5
   Dryingand dried over sodium sulfate
6. 6
   OtherThe solvent is removed in vacuo
7. 7
   Filtrationthe crude product is filtered through silica gel with heptane/toluene (4:1)

Procedure

10.6 g (38.8 mmol) of 7-bromo-6-fluoro-3-propylchroman are initially introduced in 100 ml of THF, and 27 ml (43.0 mmol) of a 15 percent solution of n-butyllithium in hexane are added dropwise. After 90 min, 10.0 g (39.4 mmol) of iodine, dissolved in 50 ml of THF, are added, the mixture is stirred for 1 h, and the cooling is removed. The batch is diluted with MTB ether, washed with water and with sat. sodium hydrogensulfite soln. and dried over sodium sulfate. The solvent is removed in vacuo, and the crude product is filtered through silica gel with heptane/toluene (4:1), giving 6-fluoro-7-iodo-3-propylchroman as a colourless solid, which is sufficiently pure for further reaction.

Source