Cesium carbonate → 2-(1,3-dioxolan-2-yl)-6,7-dihydro-5H-thieno[3,2-b]pyran

HRID 15367Notes

Reaction equation

HRID 15367 reaction equation
Br[C:2]1[CH:6]=[C:5]([CH:7]2[O:11][CH2:10][CH2:9][O:8]2)[S:4][C:3]=1[CH2:12][CH2:13][CH2:14][OH:15].C(=O)([O-])[O-].[Cs+].[Cs+]>C1(C)C=CC=CC=1>[O:8]1[CH2:9][CH2:10][O:11][CH:7]1[C:5]1[S:4][C:3]2[CH2:12][CH2:13][CH2:14][O:15][C:2]=2[CH:6]=1

Participants

4

Reactant 2

HCID 10796Cesium carbonateHCID 574869113-[3-Bromo-5-(1,3-dioxolan-2-yl)-2-thienyl]-1-propanol

Product 1

HCID 574869122-(1,3-dioxolan-2-yl)-6,7-dihydro-5H-thieno[3,2-b]pyranYield 36%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
100 °C

Procedure

3-[3-Bromo-5-(1,3-dioxolan-2-yl)-2-thienyl]-1-propanol (1.86 g, 6.3 mmol) was dissolved in dry toluene (150 ml), caesium carbonate (3.58 g, 1.5 equiv.) added, and the mixture evacuated and purged with Argon. The evacuation/purge procedure was repeated twice more. In a separate flask, were placed rac-2-di-tert-butylphosphino-1,1′-binaphthyl (Strem chemicals, 257 mg) and palladium(II) acetate (148 mg) in toluene (50 ml). The flask was evacuated and purged with argon and the procedure repeated twice more. After 10 min, the resultant yellow solution of catalyst was added to the flask containing the thiophene via syringe and the flask once more evacuated and purged with argon. The reaction mixture was heated to 100° C. under an argon atmosphere for 3 days. The reaction mixture was cooled, filtered through Kieselguhr and evaporated to low volume. The residue was chromatographed on silica gel eluting with 0-50% ethyl acetate in hexane, to afford the desired compound as a white solid (0.48 g, 36%).

Workup

  1. customthe mixture evacuated
  2. custompurged with Argon
  3. customIn a separate flask, were placed
  4. customThe flask was evacuated
  5. custompurged with argon
  6. additionthe resultant yellow solution of catalyst was added to the flask
  7. additioncontaining the thiophene via syringe
  8. customthe flask once more evacuated
  9. custompurged with argon
  10. temperatureThe reaction mixture was cooled
  11. filtrationfiltered through Kieselguhr
  12. customevaporated to low volume
  13. customThe residue was chromatographed on silica gel eluting with 0-50% ethyl acetate in hexane

Sources & evidence

ORD record
ord-0accdd24a4954a23a43bd96fcedcae3b
Source dataset
uspto-grants-2010_06
Patent number
US07732461B2

Reaction notes

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