Reaction #2507822

Reaction equation

p-toluenesulfonyl cyanide

n-butyl-lithium

7-bromo-6,6′-difluoro-3′-propyl-3,4,3′,4′-tetrahydro-2H,2′H-[3,7′]bichromenyl

→

6,6′-difluoro-3′-propyl-3,4,3′,4′-tetrahydro-2H,2′H-[3,7]bichromenyl-7-carbonitrile

Solvents

ether

THF

hexane

THF

Conditions

Workup

1. 1
   workup.WAITThe batch is left
2. 2
   Otherdoes not exceed −65° C
3. 3
   workup.WAITAfter 30 min
4. 4
   Washwashed with dil. hydrochloric acid
5. 5
   Dryingphase is dried over sodium sulfate
6. 6
   Otherevaporated
7. 7
   Otherthe crude product is chromatographed on silica gel with heptane/toluene (2:3)

Procedure

1.4 g (3.31 mmol) of 7-bromo-6,6′-difluoro-3′-propyl-3,4,3′,4′-tetrahydro-2H,2′H-[3,7′]bichromenyl are dissolved in 20 ml of THF, and 3 ml (4.8 mmol) of a 15 percent solution of n-butyl-lithium in hexane are added at −50° C. The batch is left to stir for 2 h at −70° C., and a solution of 0.9 g (5.00 mmol) of p-toluenesulfonyl cyanide in 10 ml of THF is subsequently added at such a rate that the temperature does not exceed −65° C. After 30 min, the batch is allowed to thaw, diluted with ether and washed with dil. hydrochloric acid. The org. phase is dried over sodium sulfate and evaporated, and the crude product is chromatographed on silica gel with heptane/toluene (2:3), giving 6,6′-difluoro-3′-propyl-3,4,3′,4′-tetrahydro-2H,2′H-[3,7]bichromenyl-7-carbonitrile as colourless crystals of m.p. 122° C.

Source