反应详情

Following a similar procedure to that reported in Ferraz, which is hereby incorporated by reference, to a stirred solution of 4-methyl-α-tetralone (0.867 g, 4.98 mmol) in methanol (20 mL) was added NaBH4 (0.56 g, 14.9 mmol) portionwise. The reaction mixture was followed by TLC and, after complete consumption of the starting material (about 2 h), was quenched with saturated NaHCO3. The aqueous layer was extracted with diethyl ether, dried with magnesium sulfate (MgSO4), and filtered; and the solvent was removed under reduced pressure. The crude alcohol was dissolved in toluene (25 mL) and a few crystals of p-TsOH were added. The reaction mixture was stirred overnight, then neutralized by slow addition of saturated sodium bicarbonate (NaHCO3) and extracted with diethyl ether. The combined organic layers where washed with brine, dried with magnesium sulfate (MgSO4), and filtered; and the solvent was removed under reduced pressure. The product was purified by flash chromatography (SiO2, hexanes) to give 1,2-dihydro-1,6-dimethylnaphthalene ((±)-4) as a clear oil (0.479 g, 61% yield). This compound is volatile and cannot be dried for long periods (>30 min) under high vacuum. The spectroscopic data are consistent with previously reported data (Adachi et al., Bull. Chem. Soc. Jpn., 56:651ff (1983), which is hereby incorporated by reference).

1. customafter complete consumption of the starting material (about 2 h)
2. customwas quenched with saturated NaHCO3
3. extractionThe aqueous layer was extracted with diethyl ether
4. dry with materialdried with magnesium sulfate (MgSO4)
5. filtrationfiltered
6. customand the solvent was removed under reduced pressure
7. dissolutionThe crude alcohol was dissolved in toluene (25 mL)
8. additiona few crystals of p-TsOH were added
9. additionneutralized by slow addition of saturated sodium bicarbonate (NaHCO3)
10. extractionextracted with diethyl ether
11. washThe combined organic layers where washed with brine
12. dry with materialdried with magnesium sulfate (MgSO4)
13. filtrationfiltered
14. customand the solvent was removed under reduced pressure
15. customThe product was purified by flash chromatography (SiO2, hexanes)