반응 #43428

반응 방정식

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

potassium carbonate

water

2,4,6-trivinylcyclotriboroxane

→

product

수율 77.0%

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

수율 77.0%

용매

1,2-dimethoxyethane

반응 조건

후처리

1. 1
   기타pyridine 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
   온도the mixture was cooled
4. 4
   기타partitioned between dichloromethane and saturated aqueous sodium bicarbonate solution
5. 5
   기타The layers were separated
6. 6
   추출the aqueous fraction was extracted twice with 20% methanol/dichloromethane
7. 7
   기타The combined organic solution was dried
8. 8
   기타evaporated
9. 9
   기타the residue chromatographed on silica gel
10. 10
    세척eluting with ethyl acetate

실험 절차

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%).

출처