Ethylene → 7-Ethenylbicyclo[4.2.0]octa-1,3,5-triene

HRID 543054Notes

Reaction equation

HRID 543054 reaction equation
Br[C:2]1[CH:9]=[CH:8][CH:7]=[C:4]2[CH2:5][CH2:6][C:3]=12.[CH:10]([C:12]1[CH:19]=[CH:18][CH:17]=[C:14]2[CH2:15][CH2:16][C:13]=12)=[CH2:11].C1(C)C=CC=CC=1P(C1C=CC=CC=1C)C1C=CC=CC=1C.C=C>C([O-])(=O)C.[Pd+2].C([O-])(=O)C.C(N(CC)CC)C.C(#N)C>[CH:10]([CH:5]1[C:4]2=[CH:7][CH:8]=[CH:9][CH:2]=[C:3]2[CH2:6]1)=[CH2:11].[CH:10]([C:12]1[CH:19]=[CH:18][CH:17]=[C:14]2[CH2:15][CH2:16][C:13]=12)=[CH2:11]

Participants

9

Reactant 4

HCID 6325Ethylene2×HCID 80271Tri-o-tolylphosphineHCID 117898682-Bromobicyclo[4.2.0]octa-1,3,5-triene2×HCID 713412822-Ethenylbicyclo[4.2.0]octa-1,3,5-triene

Product 2

HCID 27530077-Ethenylbicyclo[4.2.0]octa-1,3,5-trieneHCID 713412822-Ethenylbicyclo[4.2.0]octa-1,3,5-triene

Reagents, catalysts & solvents 3

HCID 167845palladium(II) acetateCatalystHCID 6342AcetonitrileSolventHCID 8471TriethylamineSolvent

Conditions

Temperature
125 °C

Procedure

The monomer is prepared by heating a mixture of 4-bromobenzocyclobutene with 4-vinylbenzocyclobutene at reflux. Vinylbenzocyclobutene is prepared by adding 0.98 g of 4-bromobenzocyclobutene, 0.04 g palladium (II) acetate, and 0.17 g of tri-o-tolylphosphine to a mixture of 100 ml acetonitrile and 0.6 g of triethylamine in a 450 ml Parr pressure reactor. The reactor is pressurized with 250 psig ethylene. The mixture is heated to 125° C. and stirred for 16 hours. The apparatus is cooled and the remaining ethylene is vented. The product is washed with water and 5 percent hydrochloric acid and dried over MgSO4. The solvent is removed to provide 4-vinylbenzocyclobutene. A 2.4 g sample of 4-bromobenzocyclobutene, a 1.7 g of 4-vinylbenzocyclobutene, a 2.4 g of tri-n-butylamine, a 100 mg of tri-o-tolylphosphine, 29 mg palladium (II) acetate and 10 ml acetonitrile are added to a fask equipped with a reflux condenser, nitrogen inlet, and magnetic stirrer. The reaction mixture is heated to reflux under nitrogen for 4 hours. The solution is cooled to room temperature and stirred into 60 ml of 10 percent hydrochloric acid solution. The precipitate is collected by filtration, washed with water and air dried. The product is recrystallized from ethylacetate and has a melting point of 132° to 133° C.

Workup

  1. customThe monomer is prepared
  2. temperatureby heating
  3. temperatureat reflux
  4. temperatureThe apparatus is cooled
  5. washThe product is washed with water and 5 percent hydrochloric acid
  6. dry with materialdried over MgSO4
  7. customThe solvent is removed

Sources & evidence

ORD record
ord-c000785f846a4e2bb1b19aa8e02e6f02
Source dataset
uspto-grants-1987_04
Patent number
US04661193

Reaction notes

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