反応 #43428

反応方程式

6,7-dihydro-5H-pyrano[2,3-c]pyridazin-3-yl trifluoromethanesulfonate

potassium carbonate

water

2,4,6-trivinylcyclotriboroxane

→

product

収率 77.0%

3-Ethenyl-6,7-dihydro-5H-pyrano[2,3-c]pyridazine

収率 77.0%

溶媒

1,2-dimethoxyethane

反応条件

後処理

1. 1
   その他pyridine complex (180 mg, 0.75 mmol) (for a preparation of this reagent
2. 2
   workup.STIRRINGAfter stirring for 2 hours at 80° C.
3. 3
   温度the mixture was cooled
4. 4
   その他partitioned between dichloromethane and saturated aqueous sodium bicarbonate solution
5. 5
   その他The layers were separated
6. 6
   抽出the aqueous fraction was extracted twice with 20% methanol/dichloromethane
7. 7
   その他The combined organic solution was dried
8. 8
   その他evaporated
9. 9
   その他the residue chromatographed on silica gel
10. 10
    洗浄eluting with ethyl acetate

実験手順

Argon was bubbled for 15 minutes through a solution of 6,7-dihydro-5H-pyrano[2,3-c]pyridazin-3-yl trifluoromethanesulfonate (228 mg, 0.8 mmol) in 1,2-dimethoxyethane (6.5 ml). Tetrakis(triphenylphosphine)palladium(0) (50 mg, 0.0435 mmol) was added and the solution stirred for 20 minutes under argon. The mixture was then treated with potassium carbonate (111 mg, 0.8 mmol), water (1.9 ml) and 2,4,6-trivinylcyclotriboroxane:pyridine complex (180 mg, 0.75 mmol) (for a preparation of this reagent see F. Kerins and D. F. O'Shea, J. Org. Chem. 2002, 67, 4968-4971). After stirring for 2 hours at 80° C., the mixture was cooled and partitioned between dichloromethane and saturated aqueous sodium bicarbonate solution. The layers were separated and the aqueous fraction was extracted twice with 20% methanol/dichloromethane. The combined organic solution was dried, evaporated and the residue chromatographed on silica gel, eluting with ethyl acetate to give product as a white solid (100 mg, 77%).

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