1,2-Dibromoethane → Ethyl 2-[5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphth-2-yl]benzoate

関与物質

反応手順

To magnesium (180 mgs, 7.5 mmols) in THF (3 ml) was added a solution of 2-bromo-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene (200 mgs) in THF (5 ml) followed by 1,2-dibromoethane (94 mgs, 0.5mmol). The mixture was stirred for 15 mins, then another portion of 2-bromo-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaph-thalene (1.14 g, 5 mmols) in THF (10 ml) was added. The mixture was stirred for 15 mins at room temperature, and refluxed for 1 h. ZnCl2 (680 mgs, 5 mmols) was added, stirred for 40 mins, and to the white precipitate. ethyl-2-bromobenzoate (1.09 g) in THF (5 ml) was added, immediately followed by addition of Ni(PPh2CH2CH2)Cl2 (26 mgs, 0.05 mmols). The mixture was stirred at room temperature for 16 h. The reaction mixture was diluted with diethyl ether : ethylacetate (1:1, a total of 180 ml), the organic phase was washed with water (10 ml), brine (10 ml) NaHCO3 (10 ml) and brine (10 ml), dried (MgSO4) and the solvent was removed under reduced pressure. Silicagel chromatography (5% ethyl acetate in hexane) followed by HPLC purification of the crude material gave the title compound as a colorless oil.

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