Reaction #1960495

Reaction equation

7,8-difluoro-2-pentylchroman-6-ol

1-hexyn-3-ol

triphenylphosphine

DIAD

→

6-(1-ethynylbutoxy)-7,8-difluoro-2-pentylchroman

Solvents

water

THF

Conditions

Workup

1. 1
   workup.ADDITIONare added over the course of 20 min with ice-
2. 2
   Temperaturecooling
3. 3
   Extractionthe mixture is extracted a number of times with MTBE
4. 4
   WashThe combined organic phases are washed with water and saturated sodium chloride soln
5. 5
   Other, and the solution is dried
6. 6
   Otherafter removal of the solvents
7. 7
   Otheris purified by column chromatography (SiO2, n-heptane:MTBE=2:1)

Procedure

10.0 g (39.0 mmol) of 7,8-difluoro-2-pentylchroman-6-ol are initially introduced in 140 ml of THF together with 4.0 g (41.0 mmol) of 1-hexyn-3-ol and 11.3 g (42.9 mmol) of triphenylphosphine, and 9.1 ml (46.8 mmol) of DIAD are added over the course of 20 min with ice-cooling. After 18 h at RT, water is added, and the mixture is extracted a number of times with MTBE. The combined organic phases are washed with water and saturated sodium chloride soln., and the solution is dried using sodium sulfate. The residue remaining after removal of the solvents is purified by column chromatography (SiO2, n-heptane:MTBE=2:1), giving 6-(1-ethynylbutoxy)-7,8-difluoro-2-pentylchroman as a yellow oil.

Source