反应详情

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%).

1. custompyridine complex (180 mg, 0.75 mmol) (for a preparation of this reagent
2. stirringAfter stirring for 2 hours at 80° C.
3. temperaturethe mixture was cooled
4. custompartitioned between dichloromethane and saturated aqueous sodium bicarbonate solution
5. customThe layers were separated
6. extractionthe aqueous fraction was extracted twice with 20% methanol/dichloromethane
7. customThe combined organic solution was dried
8. customevaporated
9. customthe residue chromatographed on silica gel
10. washeluting with ethyl acetate