反应详情

A solution of n-butyllithium (1.6M in hexane, 15.1 ml, 24.2 mmol) was added to a solution of 8-bromo-2-di-n-propylamino-1,2,3,4-tetrahydronaphthalene (5.0 g, 16.1 mmol) in THF (50 ml) at -78° and the reaction stirred at -78° for one hour. Gaseous carbon dioxide was bubbled through the reaction at -78° until the deep violet color which forms dissipates. Methyllithium (1.4M in ether, 23 ml) was added. The reaction was stirred at -78° for 30 minutes and warmed to room temperature. The reaction was stirred for an additional ten minutes at room temperature at which time the pink color had been lost. An additional 10 ml of the methyllithium solution was added and the reaction became pink once again. After 15 minutes, the pink color was lost and an additional 10 ml of the methyllithium solution added. The reaction was poured onto ice, made acidic with hydrochloric acid and extracted with ether. The aqueous layer was made basic and extracted with methylenechloride. The basic extracts were dried (Na2SO4) and concentrated to give 3.8 g of crude product. Purification by flash silica gel chromatography using 2:1 hexane:ether containing trace ammonium hydroxide provided 2-di-n-propylamino-8-acetyl-1,2,3,4-tetrahydronaphthalene as a yellow oil (2.7 g, 61%).

1. customGaseous carbon dioxide was bubbled through the reaction at -78° until the deep violet color which
2. additionMethyllithium (1.4M in ether, 23 ml) was added
3. stirringThe reaction was stirred at -78° for 30 minutes
4. stirringThe reaction was stirred for an additional ten minutes at room temperature at which time the pink color
5. additionAn additional 10 ml of the methyllithium solution was added
6. waitAfter 15 minutes
7. additionan additional 10 ml of the methyllithium solution added
8. additionThe reaction was poured onto ice
9. extractionextracted with ether
10. extractionextracted with methylenechloride
11. dry with materialThe basic extracts were dried (Na2SO4)
12. concentrationconcentrated
13. customto give 3.8 g of crude product
14. customPurification by flash silica gel chromatography